# Sodium citrate from baking soda and citric acid



## galaxyMLP (Aug 15, 2015)

So, I've seen posts about sodium citrate all over the place (for chelating) and I bought myself some citric acid to add it to my soaps. 

I've seen alot of people talking about adding extra lye to make their sodium citrate solution in their lye water. Since I'm forgetful when it comes to soaping, I kinda wanted to skip a math step. I wanted to make sodium citrate itself (dry powder). 

I decided to use baking soda because its cheaper than sodium hydroxide but is also a base. The same can be done with washing soda if you wanted to (please note the amounts for neutralization with washing soda will be different. If you want to do that, just post here and I'll do the math for you)!

After doing some math:
1 gram of citric acid (CA) is neutralized with 1.3124 grams of baking soda (BS).

1. I weighed out 200 g of CA and 263 g BS. 

2. I added 400 ml of water to a pot and added the CA till dissolved. Then I added the BS slowly!! Remember vinegar + baking soda (or even bath bombs) it with fizz up! Let it stop fizzing before proceeding. You need to stir to stop it from overflowing. I also tested the pH w/ pH paper. I wanted it to be at least 7-8. I didn't want it to be acidic b/c that would up my superfat when I used it in soap. 

3. I boiled it until the water was evaporated (maybe an hour). During the evaporation, for the last bit, it got syrup like. Then it started to cake the bottom of the pot. I recomend using a steel pot for this b/c you will get it caked on the bottom and may need to scrape some of it off. 

The theoretical yield (amount of sodium citrate I should end up with) for the amount of CA and BS I originally used was 268 g. I got 321 g because I couldn't get all the water to evaporate. Not bad though. 

Picture time:

Boiling:

View attachment 15897


Finished and labeled


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## The Efficacious Gentleman (Aug 15, 2015)

That's very cool!


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## galaxyMLP (Aug 15, 2015)

Oops! Forgot the finished picture!


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## doriettefarm (Aug 15, 2015)

Very cool galaxy!  Thanks for the tutorial on homemade sodium citrate.  I will definitely be trying this because I have plenty of citric acid and baking soda on hand for bath bombs.


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## DeeAnna (Aug 16, 2015)

Nice! Well done, Galaxy.


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## commoncenz (Aug 16, 2015)

Very nice. I will have to try this. 

Quick question. Do you think that you could have dried it out further if you had put it in the microwave on low setting for a little while?


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## galaxyMLP (Aug 16, 2015)

I didn't want to stick it in the microwave for fear of causing some small accident. Since a microwave causes water molecules specifically to move, thus creating heat, trying to heat something to the point where is contains no water honestly scares me... 

If I wanted to dry it more, I would put it in the oven at ~210-220 F in a shallow pan or baking dish for a few hours. That should get most of the moisture out.

Also, glad everyone enjoyed this! I need to do something soapy and I'm running low on lye.


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## TeresaT (Aug 16, 2015)

AWESOME!!!  I am going to do this tomorrow.  I have a heavy pressure cooker pot that would be perfect for this. I have a ton of CA.  I also just bought a 13# bag of baking soda at Costco. (OK, 5th grader time.  I put "BS" but had to delete it because I was laughing too much. Why would I pay for BS when I have so much of my own already?). 

I hope my Sodium Citrate turns out well.  Now I've gotta find that tread again with DeeAnna's science-y explanation of the amounts to use ppo. It will be so nice not to have to add extra lye.

Thanks, Galaxy!!  BTW, nice penmanship.


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## galaxyMLP (Aug 16, 2015)

I'd like you to know that I chuckled while I read your post, Theresa.  I thought about not calling it BS but... it is BS so...


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## The Efficacious Gentleman (Aug 16, 2015)

galaxyMLP said:


> Oops! Forgot the finished picture! View attachment 15907




"Honestly, officer, it IS sodium citrate. It says so on the pack!"


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## TeresaT (Aug 16, 2015)

I am doing this now.  It is on the stove at med-low and 66 deg, so it's starting to warm up.  I only had 162 cm CA left.  I mixed it with 324 gm distilled water until dissolved and slowly added 213 gm BS.  Looking at your figures, you doubled the CA for water and rounded up on the BS.  That's what I did.  However, My pH is only 6.  I used two different manufacturers, "LabRat" and the world famous "iDontRemember."  I seem to use them a lot. 

You said you wanted to keep the pH at 7-8 so it doesn't affect your SF.  I always SF at 8% for an extra buffer in case I mess up on the lye.  Especially since I use CA at 2% ppo.  Now that I don't need to add extra NAOH with this, how will a 6 pH affect the SF?  Should I just keep it at my normal 8% and leave it alone or do I need to lower/increase my SF to get the same-ish result?

FYI:  pot is at 160 deg and tiny bubbles are forming on bottom of pan.  Solution has turned from milky white to clear.  I'm totally beside myself right now!!  So. Much. Excitement.  (OK.  I really need to get out a little.)


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## galaxyMLP (Aug 16, 2015)

Is it finished reacting (not bubbling and clear)? I found that the solution stayed acidic until completely reacted. I also added a little extra BS to adjust the pH to be neutral or slightly basic. Thats what I would do! I would just add extra BS until its pH 7 or 8.


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## TeresaT (Aug 16, 2015)

"ABORT!  ABORT! We have contaminants in the pot."  

Yup!  Making sodium citrate is apparently very good for getting out deep down stains.  Once I started seeing the crud, I just dumped a bunch of tap water in there an jacked up the heat.  Now I have to find out if this is in fact the stainless steel I thought it was or just heavy aluminum.  I'm guessing heavy aluminum. Thank heavens I didn't try this with NaOH!  

In answer to your question, I thought it was finished reacting.  It was not bubbling; however, it was not clear.  Now, in retrospect, it was still reacting.  It was slightly foamy.  It looked like skim milk that has been heated. It was foamy, but didn't look like it was still doing anything, so I thought it was OK.  I put it on to cook and then I though about dogging out the pH strips.  It was 51 deg when I put it on and the 60 whatever when I tested it.  I'll try again after I buy some more CA an this time I'll know to wait until it is clear with no bubbling before testing the pH and putting it on to boil.  At least I've a clean pot.

ETA:  oh, yeah!  Presto Pressure cooker 409A is aluminum.  Thank you for not making your sodium citrate with NaOH.  I would most likely be dead or very sick right now!  But, on the plus side, I have found an easy way to safely clean stubborn stains from pots and pans.   And my pot is now ready to make clean sodium citrate. (Unless you think I should put this away and get out my huge stainless steel soaping pot?)


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## galaxyMLP (Aug 16, 2015)

I believe the aluminum pot should be OK! I would also have just strained the crud out of the solution of CS I wouldn't worry about it too much. Did you already toss your solution?

Next time I would also test it when it gets around 100-130 F or so degrees while on the heat. This way it's more likely that the reaction has gone to completion. You can always add more BS at any point (except once it's dry of course). It will keep dissolving/ raising the pH as you add more.


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## TeresaT (Aug 16, 2015)

Yup.  Totally down the drain.  It was pretty nasty looking, kinda brown liquid more so than anything to be strained.  The SC would have been grayish looking when it dried, I think.  I'll pick some CA up at the grocery store tomorrow. It has an anti-caking agent in it, I don't remember what it is right now, but that won't make a difference, will it?  I can always order the CA from Dianna's sundries and pick it up Tuesday. She might actually sell SC.  But I want to make it.  It's got more wow factor to it.


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## galaxyMLP (Aug 16, 2015)

Ohhh, ewwwie, brown. Lol. Quick question, what did you use to stir it? If it was silverware with actual silver, it will clean that too. Baking soda+ aluminum+silver=tarnish remover on silver. It's pretty amazing. I did a little science fair project on it in high school.  so, dont use metal silverware to stir it, else you might end up with more brown flakies next time too!


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## TeresaT (Aug 16, 2015)

No metal but the pot.  I used my rubber soaping spatula.  Good to know, though.  The bottom of the pot has stains on it, too.  Do I just need the baking soda to clean it or do I need the CA, too? I don't know if my pot looked that good when I bought it, to be honest.


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## galaxyMLP (Aug 16, 2015)

Lol. I have no idea about cleaning the pot honestly. I wanted to give you some explanation but I got nothing. I would think the reaction lifted the stains and the heat from boiling with the solution probably helped. Really don't know for sure though...

If you wanted to know for sure, I'd get 3 pots, purposely tarnish/burn something on them (same material pot or same pot just 3 times), and try one with just BS one with just CA and one with the CS reacting mixture. See which is best. Might be good to know!!


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## Dahila (Aug 16, 2015)

I am going to try it too


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## TeresaT (Aug 16, 2015)

Post a picture of your clean pot, Dahila.


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## Dahila (Aug 17, 2015)

I swear I posted here , with questions but maybe I had done it in the wrong thread)
Galaxy so I need to use stainless pot and on very low heat ,  then if I get something like you had, How much would you use PPO? 
I use citric acid now. On you tube is a lot of vids but only the solution,  I will try and if success will post)


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## galaxyMLP (Aug 17, 2015)

I'm not sure I'm understanding what you mean by low heat? You need to boil off the water so I would actually put the mixture on the stove on high heat not low heat. You can start it on no heat until it finishes reacting (is clear with no bubbles) and your pH is 7-8; then you can put it on high heat.

I would use around 1-3% like with EDTA. Just dissolve it in a bit of water before adding it to your mix or add it into your lye solution. Just make sure you're not using a super concentrated lye solution (example, 50%). Otherwise the sodium citrate wont dissolve for the higher %. 

The percentage use is going to depend on how hard your water is. My water is very hard so I'm using about 2.5-3% of the total batch weight (not per the oil amounts). However, because this isn't going to react with the soap itelf and is only to help mitigate hard water/soap scum issues, exactly the same percentages/measurments each time are not super critical. I'd play with it a bit and see what helps.


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## Dahila (Aug 17, 2015)

Galaxy thanks, I thought is should evaporate slowly, but ok.  so I actually use it like CA but I do not have to add extra lye.  
One more problem.  I have no PH paper to check the ph.  of solution


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## galaxyMLP (Aug 17, 2015)

Dahila said:


> Galaxy thanks, I thought is should evaporate slowly, but ok.  so I actually use it like CA but I do not have to add extra lye.
> One more problem.  I have no PH paper to check the ph.  of solution



Thats ok! Dont worry too much about the pH.  It really wont affect the superfat much as long as you add the correct amounts of BS and CA in the beginning. I just did that as a check for myself to see that it worked. Chances are you have reacted almost all of the CA and BS. Another interesting way to check would be to add pinches of BS to the solution and watch it to see if its reacting. If it no longer fizzes when you add pinches of BS, you've consumed all the CA and you're good to go!

You can have it evaporate slowly if you want, I'm just an instant gratification kind of person. You can even just let it sit out and evaporate on its on if you wanted! depends on how patient you want to be!


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## Dahila (Aug 17, 2015)

Thank you so much , all my questions answered,  you are a jewel Galaxy , will post with the results maybe this week,


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## galaxyMLP (Aug 17, 2015)

The Efficacious Gentleman said:


> "Honestly, officer, it IS sodium citrate. It says so on the pack!"



I forgot to say something about this! He he. I thought that as I was bagging it up. Then I thought, what will my roommate think of all of these little crystals on the floor (oops! I spilled some...)?

My boyfriend has called me "Wendy White" after Walter White. I haven't even told him about this newest experiment!


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## TeresaT (Aug 18, 2015)

Second attempt.  I'll go pour olive oil from the big bottles to the small bottles while this finishes reacting.


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## galaxyMLP (Aug 18, 2015)

Looking good!!


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## TeresaT (Aug 18, 2015)

It still foams and bubbles when I stir it.  Is that normal?  This is what it looks like now.


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## TeresaT (Aug 18, 2015)

After stirring.  It's actually a lot less now.  I think I'll just leave it overnight and cook it when I get home from work.


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## galaxyMLP (Aug 18, 2015)

Okays! Yes, it shouldn't fizz at all when mixed. If you start heating it at that final stage that will help get those last "fizzies" out by making the reaction go faster.


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## sudsy_kiwi (Aug 18, 2015)

Could someone please offer a quick "Dummies Guide" version of the pros/cons of Sodium Citrate vs just adding Citric Acid?  I've only just started adding CA to my soaps to combat hard water (they're still curing, so I haven't even tried them yet) and now I'm wondering if I should be using SC instead? :Kitten Love:

Cheers,
SK


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## DeeAnna (Aug 18, 2015)

See http://www.soapmakingforum.com/showthread.php?p=506213 especially post 14

Eta ... I should,also add it doesn't matter whether you use,citric acid and the appropriate extra lye or whether you use sodium citrate, at least as far as the soap is,concerned. It might make a difference to your soaping process whether you use on or the other ... one might be more convenient or easier to use or whatever.


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## galaxyMLP (Aug 18, 2015)

You need to add additional lye and calculate it out every time you use citric acid in your lye water/soap batter.

This is because lye (sodium hydroxide, in this case) is a base and citric acid is, well, an acid. Acid + base = neutralization in the simplest sense. Thus, you are neutralizing some of your base. But, it's supposed to react with your soap, and is instead reacting with your citric acid. This leads to an artificially high superfat. To combat this, you have to add extra lye when you make each an every batch of soap to neutralize the amount of CA you are adding without eating up your lye that you want to react with your soap. When you add the extra lye and are reacting the CA, you are making sodium citrate in that exact moment. Same stuff I'm making here!  

Making the sodium citrate just removed that last step of adding the extra lye in to the original mix. That way I don't have to calculate out adding extra lye from the get go. In that case, I weigh it just like every other additive and the amounts become much less supercritical.

Edit: aaand, Dee beat me to it, albeit with alot less words! Haha.


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## commoncenz (Aug 19, 2015)

One other thing of note: Making Sodium Citrate using baking soda, as Galaxy has shown us how to do, will actually save you money in the long run if you are making a lot of soap. The cost of the extra lye that you would use to convert the CA to SC in your soap will add up over time (even though it is just a little extra). Baking soda is cheaper than lye. 

I know I sound like a penny pinching skin flint, but ... lol


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## sudsy_kiwi (Aug 19, 2015)

Thank you all for your help.  One little follow-up...how do I calculate the extra lye needed if I continue to just use CA?

And hey, I'm all about pinching pennies where I can, so I'll have a crack at making up some SC 

ETA:  Ooops, disregard the above, I'm apparently having a blonde/senior/tired moment.  Just went and re-read the thread linked above and found this... "10 g citric acid neutralizes 6.24 g NaOH"

Thanks again
Matt


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## cmzaha (Aug 19, 2015)

sudsy_kiwi said:


> Thank you all for your help.  One little follow-up...how do I calculate the extra lye needed if I continue to just use CA?
> 
> And hey, I'm all about pinching pennies where I can, so I'll have a crack at making up some SC
> 
> ...



I figured out my needed citric by oil weight at 2.5%, then multiply the answer by 0.624 for the extra lye. 
Since I soap with 50/50 lye solution I add on the extra lye needed to the total lye * 2 for total lye. All the info goes on my recipe sheet so I do not forget the additional lye


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## TeresaT (Aug 19, 2015)

Just burned the sodium citrate.  Very annoyed.  Tomorrow after work, when both the pot and I have cooled off, I will get out the hammer and chisel.    And now we know why I don't cook anymore.


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## DeeAnna (Aug 19, 2015)

Try adding some water and let it soak. That may help!


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## TeresaT (Aug 19, 2015)

I started to do that, but thought that would defeat the purpose of cooking it.  But, I feel better that you've made the suggestion, DeeAnna.  Thanks.  I'll go toss some distilled water in it and see what happens.  If it's a total mess-up, where do I buy sodium citrate?


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## DeeAnna (Aug 19, 2015)

Actually, what's wrong with using sodium citrate as a water-based solution? Maybe the universe is pointing the way for you to use it that way rather than in solid form? After all, you're just going to dissolve the citrate in water later on when you make soap. 

You know what weight of citric acid you started with. Assuming you used exactly the right amount of baking soda or a slight excess of baking soda, you can reasonably assume all of the citric acid converted to sodium citrate. Using Galaxy's relationship of "..1 gram of citric acid (CA) is neutralized with 1.3124 grams of baking soda (BS)...." then you can figure out the total weight of sodium citrate.  The rest is water and maybe a little leftover baking soda -- but for all intents and purposes let's call it 100% water. Based on what I'm seeing on Google, you should be able to make a 50% solution by weight. That means to dissolve 100 grams of sodium citrate in 100 grams of water to make a total of 200 grams of solution.

ETA: 1 g citric acid + 1.31 g baking soda => 1.34 g sodium citrate + carbon dioxide gas + water. See also post 51 below.


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## TeresaT (Aug 19, 2015)

DeeAnna said:


> Actually, what's wrong with using sodium citrate as a water-based solution? Maybe the universe is pointing the way for you to use it that way rather than in solid form? After all, you're just going to dissolve the citrate in water later on when you make soap.
> 
> You know what weight of citric acid you started with. Assuming you used exactly the right amount of baking soda or a slight excess of baking soda, you can reasonably assume all of the citric acid converted to sodium citrate. Using Galaxy's relationship of "..1 gram of citric acid (CA) is neutralized with 1.3124 grams of baking soda (BS)...." then you can figure out the total weight of sodium citrate.  The rest is water and maybe a little leftover baking soda -- but for all intents and purposes let's call it 100% water. Based on what I'm seeing on Google, you should be able to make a 50% solution by weight. That means to dissolve 100 grams of sodium citrate in 100 grams of water to make a total of 200 grams of solution.



This made my brain hurt.    I don't know why I made it powder, either, except that's what Galaxy did and I'm a copycat.  The only thing I can think of is to get all of the sodium citrate separated from the water so that I *could* make a 50% solution by weight.  If I used the wet or damp stuff, my solution concentration would be off, wouldn't it?  Also, if I used wet or damp stuff in my soap, wouldn't that make my usage rate off?  My brain really hurts now.

Drying now.  I'll see tomorrow how much I ended up with after all of my mistakes.  But, it was fun learning how to make a real chemical in my kitchen.


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## galaxyMLP (Aug 19, 2015)

What Dee says would probably be best in the future. I'll probably honestly do that from now on. In my head though, I liked the idea of having a dry powder instead of yet another jar of liquid in my tiny (carpeted) apartment. 

If you have the room for it, I would say go for it if evaporating it isn't working for you.  She's right you know, you ARE just going to dissolve it again. 

Dee, the voice of reason.

Also, I'm VERY sorry this didn't work for you  it makes me sad when other people have a hard time due to something I wrote or had a hand in. Again, I'm sorry.


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## commoncenz (Aug 19, 2015)

DeeAnna said:


> Actually, what's wrong with using sodium citrate as a water-based solution? Maybe the universe is pointing the way for you to use it that way rather than in solid form? After all, you're just going to dissolve the citrate in water later on when you make soap.
> 
> You know what weight of citric acid you started with. Assuming you used exactly the right amount of baking soda or a slight excess of baking soda, you can reasonably assume all of the citric acid converted to sodium citrate. Using Galaxy's relationship of "..1 gram of citric acid (CA) is neutralized with 1.3124 grams of baking soda (BS)...." then you can figure out the total weight of sodium citrate.  The rest is water and maybe a little leftover baking soda -- but for all intents and purposes let's call it 100% water. Based on what I'm seeing on Google, you should be able to make a 50% solution by weight. That means to dissolve 100 grams of sodium citrate in 100 grams of water to make a total of 200 grams of solution.



Question ... never mind ... I was going to ask if, since you usually dissolve sodium citrate in a 2:1 solution, wouldn't you then have to add extra water before adding to your oils?

However, if you have completely dissolved your sodium citrate in a 1:1 solution, you wouldn't have to do this. You'd just weigh out your solution so that you have the correct amount of sodium citrate for your recipe and account for the water by discounting that amount from your lye solution ... So, if your recipe called for 1.7 Oz of sodium citrate, you would weigh out 3.4 Oz of solution, which would be 1.7 Oz of both water and sodium citrate. Then you would account for the 1.7 Oz of water by discounting that amount from your lye solution ... correct?

(still using Oz here 'til I get a scale that goes down to the .01 grams)


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## galaxyMLP (Aug 19, 2015)

Yeppers. Exactly that. 

Remember that about 30 grams are in 1 oz so a scale that can weigh up to 0.05 oz is still better off being used in grams b/c that is actually more accurate. Even if you round to the gram, its better than 0.1 oz.


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## TeresaT (Aug 19, 2015)

galaxyMLP said:


> What Dee says would probably be best in the future. I'll probably honestly do that from now on. In my head though, I liked the idea of having a dry powder instead of yet another jar of liquid in my tiny (carpeted) apartment.
> 
> If you have the room for it, I would say go for it if evaporating it isn't working for you.  She's right you know, you ARE just going to dissolve it again.
> 
> ...




Silly girl!  Don't be sorry!  This was all good.  It's an experiment.  I'll try it again and do better next time.  (By that, I mean stay in the kitchen where the boiling pot is and off the internet!).  You're a scientist.  You know not everyone gets it right the first time out.   

I'm still trying to wrap my brain around the solution thingy.  What would have been the usage rate of the liquid I ended up with in the first place?  I mixed 200 mg CA with 263 mg BS in 400 mg water.  So, once all of it stopped reacting what was in my pot?  Would there still have been 863 mg of "stuff" in my pot and how much of that would be SC and how much H2O.  Oh, no.  My brain hurts again.


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## DeeAnna (Aug 19, 2015)

Teresa ... the amount of citrate you made can be calculated based on the citric acid you weighed out to begin with ... you don't have to dry the stuff out to get that weight. 

Gosh ... I'm on my kindle right now (lying in bed totally goofing off, if you must know) and don't have my calculator close to hand. I need to sit down tomorrow at my desk (where I left my geek hat for the night) and figure this out for you. Or Galaxy can if she's so inclined!


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## DeeAnna (Aug 19, 2015)

The final weight of stuff won't equal the weight of what you started with cuz some of it fizzed off or evaporated  into the air.


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## galaxyMLP (Aug 19, 2015)

galaxyMLP said:


> The theoretical yield (amount of sodium citrate I should end up with) for the amount of CA and BS I originally used was 268 g. I got 321 g because I couldn't get all the water to evaporate. Not bad though.



That is what you are looking for. So in this case, you would do a solution with 268 grams of water with your initial 200 g CA and 263 g BS. That gives you 268 g of SC, which has to be at least 50% concentration. I hope that helps! I'm off to bed not though so I'll have to answer any other questions in the morning.


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## TeresaT (Aug 19, 2015)

DeeAnna, don't worry about it.  I don't want you to go through more trouble than you already have.  I weighed my sodium citrate a little while ago.  I have 99 gm!  When that water "softened" up the caked stuff on the bottom of the pot, it probably dissolved some of it.  And when I poured it through the strainer to catch the chunks, I probably should have saved that "water." 

I really should not do "brainpower" stuff after working all day.   That is why I only soap on the weekends and quit cooking a few years ago.


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## DeeAnna (Aug 20, 2015)

Hey, Teresa, good save! After a cuppa joe this morning, I rummaged around, found my geek hat and paraphernalia, and re-read Galaxy's original post. She did all the math for us already!

Galaxy's original recipe:

400 g distilled water
200 g citric acid
263 g baking soda

After following her procedure for mixing this up, the chemical reaction will create 268 g trisodium citrate (aka sodium citrate). When you get the baking soda all dissolved and everything stops fizzing, you'll have 268 g sodium citrate plus some water and perhaps a bit of leftover baking soda. 

If you don't want to evaporate the citrate to a dry powder, I would suggest making a 50% sodium citrate solution. To do this: 

Weigh the solution you've just made. The weight of water in the solution after everything is all reacted will be:
After-the-reaction water weight = Total solution weight - 268 g of sodium citrate

If you add enough extra water to this mixture so the total water is equal to 268 g, then you will have a 50% solution of sodium citrate. In other words:
Water to add to make a 50% solution = 268 g - After-the-reaction water weight

***

To scale this recipe up or down, you can use this relationship:

1 gram citric acid plus 1.31 g baking soda gives you 1.34 g sodium citrate.

***

To use, figure the weight of pure sodium citrate you want to add to your soap batch. Since every gram of your solution has only 0.5 g of citrate, use TWO TIMES that weight when measuring out your 50% sodium citrate solution.

What dosage of citrate to use in soap?  A typical dosage for citric acid is about 1% ppo. The equivalent dosage of sodium citrate is 1.3% ppo. You can do 2 or 3 times that amount, if needed.


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## galaxyMLP (Aug 20, 2015)

I was hoping you would see that! I also quoted it in the post I made last night. Thank you for elaborating.


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## commoncenz (Aug 20, 2015)

I guess it probably doesn't matter since I will most likely stick with Galaxy's numbers. However, how did you come to 400 ml of water originally? Also, if I am doing my math correctly one could expect a conversion rate of roughly 0.58? By that I mean your yield of sodium citrate will be approximately equal to .58 of the total weight of CA and BS you used to create the sodium citrate.


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## galaxyMLP (Aug 20, 2015)

commoncenz said:


> I guess it probably doesn't matter since I will most likely stick with Galaxy's numbers. However, how did you come to 400 ml of water originally? Also, if I am doing my math correctly one could expect a conversion rate of roughly 0.58? By that I mean your yield of sodium citrate will be approximately equal to .58 of the total weight of CA and BS you used to create the sodium citrate.



Sometimes in life, numbers just come to us. I just wanted some amount that my CA and BS could be easily dissolved in and I picked 400 g. Its completely arbitrary in this case. No math was done to get the magical number of 400. 

I don't want to comment on the conversion rate yet (it should work but, just to make sure, I want to do more maths).


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## commoncenz (Aug 20, 2015)

galaxyMLP said:


> Sometimes in life, numbers just come to us. I just wanted some amount that my CA and BS could be easily dissolved in and I picked 400 g. Its completely arbitrary in this case. No math was done to get the magical number of 400.
> 
> *I don't want to comment on the conversion rate yet (it should work but, just to make sure, I want to do more maths)*.



Sounds totally fair. Please let us know when you have arrived at a conclusion. And again, thanks for this.


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## TeresaT (Aug 20, 2015)

Thank you!  That makes sense now.  I can wrap my little-bitty brain around that math explanation!  I have actually found and ordered food grade SC; however, now that I understand better the idea behind making the solution, I'm going to play with it a little more.  Just because CA & BS are readily available at Ace hardware and if I can learn to make my own solution, I won't ever have to worry about running out.


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## Dahila (Aug 21, 2015)

I have a difficulties with the 50% solution.  Half of that is water yes?  Am I wrong?  Let's say I am adding SC solution but 25% of that is water? Help me out wise woman)


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## galaxyMLP (Aug 21, 2015)

Sorry, I'm a little confused by your question.

Do you mean, what if you have a 25% solution of SC? 

In that case you have 1 part SC to 3 parts water.

However, the way you wrote it (25% of that is water) , I read it as you are trying to dissolve 3 parts SC in 1 part water which is not possible?

ETA: and yes, for a 50% solution, half of it is water.


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## DeeAnna (Aug 21, 2015)

"...Half of that is water yes? Am I wrong?..."

You are right -- that is correct, Dahlia.

"...Let's say I am adding SC solution but 25% of that is water?..."

I don't think it is possible to make a 75% solution of sodium citrate and 25% water. I think a 50% solution is about the most concentrated sodium citrate solution possible. 

***

So let's talk about a more practical solution of 25% citrate and 75% water. If that is the case, then here is an example of how to calculate the amount of solution to use in your recipe --

Example: You want to add 10 grams of pure sodium citrate to a soap recipe. If you are using a 25% solution of sodium citrate, then you would add this much citrate solution: 
Weight of 25% citrate solution = (100 / 25) x 10 grams = 40 grams.

See how the 25 percent is used as a fraction in this example? You can simplify the fraction "100/25" to just "4" if you like. The number "4" is certainly easier to remember, but not every percent works out this nicely. Bear with me and look at this next example --

***

If you COULD make a 75% solution of sodium citrate in water -- just pretending here -- then the math to get a total of 10 grams of sodium citrate using a 75% solution is this:
Weight of 75% citrate solution = (100 / 75) * 10 grams = 13.3 grams.

The fraction of 100/75 doesn't make a nice easy number like the previous example of 100/25, so the fraction of "100/75" is probably the easiest to use in this case.

***

You can use the same method with a 50% solution that we've been talking about in previous posts. Here is an example of how to calculate the correct amount of sodium citrate if using a 50% solution --

Example: You want to add 10 grams of pure sodium citrate to a soap recipe. If you are using a 50% solution of sodium citrate, then you would add this much citrate solution: 
Weight of 50% citrate solution = (100 / 50) x 10 grams = 20 grams.

Again, the fraction of 100/50 can be simplified to a convenient "2" that is easier to remember. This 50% example and the 25% example show you why people tend to stick to these percentages rather than using other percentages. The math is easier.

I hope this helps.

ETA: Please note the maximum concentration for sodium citrate in water is roughly 40% -- 40 grams SC + 60 grams water. Many thanks to Patrick for providing this information -- see Post 71 below. I updated my original recipe -- see Post 83 for the latest version.


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## jiroband (Aug 21, 2015)

I'm sorry for interrupting from out of no where, but what are you making sodium citrate for? 

I tried to follow this from the beginning, but I must have gotten lost along the way.


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## galaxyMLP (Aug 21, 2015)

Sodium citrate acts as a chelator for the metals found in hard water. It reduces the amount of soap scum that forms when added in an amount of 1-3% of the amount in a batch.

I have very hard water where I live so I wanted to try this. 

Another great chelator out there is EDTA. However, with all of the "natural" junkies out there, sodium citrate "sounds" better (and, in my opinion, can be cheaper in the long run [thats really why I like it])

ETA:
Soap scum is formed when insoluble salts of fatty acids are created. Sodium and potassium salts of fatty acids (solid and liquid soap respectively) are soluble in water. However, calcium, magnesium and other metal salts of fatty acids are not soluble in water. This is what causes soap scum or tub ring. 

ETA2: Chelators are basically chemicals that have available sites on them that can bind to other ions. They effectively take up the "reacting power" or "binding power" of many different ions (for example calcium in this case)


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## DeeAnna (Aug 21, 2015)

The purpose of citrate (or tetrasodium EDTA) is to chelate (bind up) metals. Adding a chelator (aka chelant) to your soap batter will reduce the chance that your soap will become rancid (get DOS) as time passes due to metallic impurities. 

A chelator in your soap also reduces the amount of soap scum that occurs when lye soap reacts with hard water minerals while you shower or bathe. Soap scum can make your skin sticky, itchy, and sometimes irritated and can also reduce the lather your soap makes.

*CITRIC ACID in Soap*
Typical dosage: 10 g citric acid for every 1,000 g oils (1% ppo). Range 0.1% to 3%.
Citric acid reacts with lye, so you MUST add additional lye (NaOH or KOH) needed for the citric-lye reaction. If you do not add this extra lye, your superfat may be higher than you want it to be in your finished soap. In bar soap, this extra superfat may reduce lather and may make the bar softer. In liquid soap, this may cause fats to separate out and float on your diluted soap. 

Citric acid and Sodium hydroxide (NaOH) make Sodium citrate in soap
10 g citric acid neutralizes 6.24 g NaOH

Citric acid and Potassium hydroxide (KOH) make Potassium citrate in soap
10 g citric acid neutralizes 8.42 g KOH

Stir the citric acid into the water you will use to make your lye solution. Add the lye to the water and proceed with your recipe as usual.

*SODIUM CITRATE or POTASSIUM CITRATE in soap*
If dosage rate for citric acid is 1%, the equivalent dosage for sodium citrate is 1.3%
If dosage rate for citric acid is 1%, the equivalent dosage for potassium citrate is 1.6%

Do NOT add additional lye if you are using potassium or sodium citrate. Extra lye is only needed if you are using citric acid.

Stir the citrate into the water you will use to make your lye solution. Add the lye to the water and proceed with your recipe as usual.

*EDTA in Soap*
EDTA comes as a powder. Typical dosage is 0.5% of EDTA powder based on batch total weight (fat + lye + water). 

You can dissolve the powder directly in your lye water, but most of us make a water and EDTA solution and add the solution to the lye water or oils. The solution most of us use is 39% EDTA dissolved in distilled water (39 g EDTA + enough water to = 100 g of solution). Since you need so very little EDTA, it is easier to measure as a solution rather than as the powder.

Be sure to purchase TETRAsodium EDTA, not DIsodium EDTA. Tetra is for alkaline products like soap. Di is for neutral to slightly acidic products.

More about EDTA and citrate: http://www.soapmakingforum.com/showthread.php?p=509320
ETA: And here's more background: http://www.soapmakingforum.com/showthread.php?t=52456

PS: My apologies to those who have seen this before. Thought I'd just repeat myself and save a little time.


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## jiroband (Aug 21, 2015)

Interesting. Thanks for the info!

Jim


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## DeeAnna (Aug 21, 2015)

I'm making up a sodium citrate solution this afternoon, but I'm doing it at room temperature, rather than heating it. 

My initial recipe:

100 g citric acid
131 g baking soda
134 g distilled water

Theoretically, the yield of sodium citrate is 134 g, so that is why I decided to use 134 g of water.

My goal was to make a 50% solution of citrate and water. I didn't allow for water that the reaction itself is creating, so I think I'm going to end up with a slightly less concentrated solution than I had planned. Small matter. 

What's cool is this is an "endothermic" reaction, meaning one that absorbs heat from the environment. My container and the fizzy liquid inside are actually quite cold. The process is slow as well -- I mixed up my ingredients about 3:30 p.m. and the mixture is STILL fizzing gently two hours later.

I'll update this later....

ETA: I updated this recipe -- see Post 83 for the latest version.


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## Dahila (Aug 21, 2015)

DeeAnna thank you so much, I know i should formulate my questions better after 25 years in Canada and thousand and one books I had read, but I am older lady. Forgive me, and thank you. 
Galaxy hee it is normal not to understand me, sometime I do not understand myself. Thanks to kind people here, I  actually feel welcome, on the forum)


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## SunWolf (Aug 21, 2015)

DeeAnna said:


> <snip>  *Stir the citric acid into the water you will use to make your lye solution.* Add the lye to the water and proceed with your recipe as usual.  <snip>
> 
> PS: My apologies to those who have seen this before. Thought I'd just repeat myself and save a little time.




Thank you, thank you, thank you for repeating yourself!   It has finally sunk into all the holes in my swiss cheese brain, and the math finally makes sense.   It's been fun making my brain stretch a bit, it's been a while.   :grin:

However, I have a question about the above instructions about how to add the CA.  I use raw goat milk as full liquid for almost all of my recipes...citric acid and milk do not play well together...

  ...well, unless, of course, you are actually _wanting_ to make cheese!!   But that's a whole 'nother obsession I'm just getting started on!   

So, since I want to make soap instead of cheese, can I add the additional  lye to the lye solution, and blend the CA into my oils? 

I'm thinking the oils will dilute the CA a bit to keep the milk from curdling, and the extra lye will already be working on the goat milk, so it should work out OK??  Maybe??


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## galaxyMLP (Aug 21, 2015)

Considering you have a huge excess of lye (a base) and are adding only a small amount of CA that will be neutralized, I would still add it to the lye solution in your case. Add the CA after you make up you lye solution with the excess lye to neutralize the CA.

This is because in your case, the goats milk won't even "see" the acid to react with it and curdle. The lye will "see" the CA and react with it. This means you have no more acid left in your solution but still have the lye left to react with your oils in your recipe. 

You can't add CA to your oils because it is not soluble in oil (it won't dissolve!) That means you might get granules of CA in your soap if it doesn't get a chance to dissolve when you add the lye water! 

Please note for all those interested above, in this case I am referring to adding citric acid and not sodium citrate as I have been talking about this whole time. Sodium citrate does not need any extra lye.

You know, you could also just make up sodium citrate with the baking soda and not have to worry about neutralization at all!


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## SoapSap (Aug 21, 2015)

Is sodium citrate also used to prevent DOS, just as TRISODIUM Citrate?


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## DeeAnna (Aug 21, 2015)

SunWolf -- I agree with Galaxy that the citric acid should be dissolved in a water-based liquid to make sure it dissolves completely. I can also appreciate your concern about the acid curdling your soap. Perhaps the compromise is to dissolve the citric acid in a small amount of water and when it is dissolved, then blend that liquid into your fats. You should be able to dissolve citric acid in an equal weight of water or a bit more, so it won't take much water. Galaxy makes an even better point that sodium citrate may be the best thing to use, because it avoids the whole issue of exposing your milk to an acid  at any point in the game.

Update on my experiment -- it's now about 6 hours since I first mixed up my ingredients. The fizzing has stopped. What I've got is a whitish crystalline material in a water-clear but slightly syrupy liquid. The effect is like a partly melted slushy (snow cone). I'm going to leave it alone overnight and see what it looks like in the morning. I'd like this to be a fully liquid solution, so it looks like I'm going to have to dilute this further to reduce the concentration and get the crystals to dissolve. I thought from my reading that sodium citrate is soluble in water up to a 50% concentration, but obviously I'm wrong on that point!

I should add -- If you are considering trying this for yourself, I want to warn you to mix your ingredients in a generously large container. The container should be at least 5 or 6 times larger than the volume of your ingredients, because this stuff foams up A LOT. For example, I mixed my 365 grams of ingredients in a 1 liter beaker and that wasn't quite big enough -- I had to watch it like a hungry hawk for about 45 minutes. It will also work better if your container is as wide or wider as it is tall, because the foam that is created will break down easier in a wide, shallow container than in a tall, narrow one. Plan to sit with your experiment for at least an hour and stir as needed until the foaming slows down and doesn't threaten to overflow. At that point, you can put your experiment in a safe place out of reach of pets and children and let it quietly fizz away for a few more hours on its own.


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## DeeAnna (Aug 21, 2015)

Sodium citrate IS trisodium citrate, at least this is the typical version you'll find in general commerce. You can get mono- and di-sodium citrate as well for specialty uses.

"...Trisodium citrate has the chemical formula of Na3C6H5O7. It is sometimes referred to simply as sodium citrate, though sodium citrate can refer to any of the three sodium salts of citric acid...." https://en.wikipedia.org/wiki/Trisodium_citrate


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## commoncenz (Aug 21, 2015)

DeeAnna, don't know how much (if any) this helps, but 1 gram of SC dissolves in 1.3 grams of water at around room temperature, so it's not a true 1:1 ratio for solubility. 

https://www.sigmaaldrich.com/content/dam/sigma-aldrich/docs/Fluka/Datasheet/71401dat.pdf

Solubility is mentioned under "Preparation Instructions"


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## DeeAnna (Aug 22, 2015)

Good stuff, Patrick -- thank you for digging that up; I appreciate the info. A 1:1.3 dilution would be about 43% concentration of sodium citrate. From a practical sense, I'd probably use a 40% concentration max to allow for temperatures cooler than 25 C (77 F).

I diluted my mixture to a 33% concentration (1 part citrate to 2 parts water) this morning. (That was before I read your post, Patrick, or I would have tried a 40% concentration instead!) Almost all of the crystals dissolved within seconds, but there is a small amount of solids remaining. I'll see if a bit of time will help the last bits to dissolve.


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## sudsy_kiwi (Aug 23, 2015)

Just to go off on a wee tangent, is it possible to add SC or CA to M&P soap?  And if so, how would you suggest doing it?
With our hard water here, even M&P seems to dry my skin something terrible.


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## DeeAnna (Aug 23, 2015)

I don't have any M&P experience, so I can't say for sure, but I'll offer my opinion based on things I've heard from people who do M&P. 

I rather doubt it would work well to add either one, given the cautions I hear from others about adding other ingredients to this type of soap. If it would work to add a chelator, then I'd use sodium citrate only. You'd only want to add citric acid to a soap if there is enough extra lye added for the acid to be able to turn into sodium citrate. Is there extra lye in M&P? If not, then any added citric acid would probably break down the M&P soap and make a mess. That wouldn't be a good idea. 

I also want to add that hard water makes soap scum, which can be sticky and unpleasant on the skin, but soap scum isn't the same as the soap being drying to the skin. That comes from the formulation of the soap itself. I have heard some formulations of M&P can be harsh, so maybe you need to consider another base? Many people swear by SFIC bases, if you're looking for a suggestion. Again I'm just repeating what I've heard -- I don't have personal experience.


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## galaxyMLP (Aug 23, 2015)

I agree about the soap scum not feeling drying to the skin. It may feel a little itchy and sticky but it shouldn't feel drying. Since MP soap does have some water and other solvents in it, you may be able to add a small amount of SC to it and see if it dissolves just adding it directly to melted soap

Alternatively, SC may dissolve in glycerin a little bit. Try warming about 15 grams (~1 tablespoon) of glycerin and adding 1-5 gram of SC. Start w/ 1 gram and keep adding SC till it won't dissolve any more. 

How I would do it:

1. Place 15 grams glycerin in a little bowl and warm it to ~100 F
2. Weigh out 1 gram of SC into 5 containers (total, 5 grams) 
3. Add 1 container to the glycerin
4. Stir stir stir
5. Repeat until you stop getting it to dissolve.

You can add up to 1 tablespoon glycerin to 8 oz of MP soap.


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## commoncenz (Aug 23, 2015)

OK, just got done taking a batch of the solid form out of the pot and placing it in the oven to see if I can get it to dry a little more. What I did was to take it out of the pot when it was still very moist and put it into the oven (on parchment paper) at 210 degrees Fahrenheit. I will watch it carefully and use my steel spoon to keep it broken up a bit. Maybe after it is "dry" I'll run it through the blender on pulverize to see if I can get a powder.

I wanted to try to make the solid state SC first as I am a glutton for punishment. :mrgreen:

I would add pics, but my phone is acting funny.


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## DeeAnna (Aug 23, 2015)

Nice refinement to the method, Patrick! I like the idea of heating the sodium citrate to dryness in the oven or in a dehydrator if a person has one. Much less chance of overheating than the stovetop method. While I'm sure the stovetop would work fine for many, I'm definitely too absent minded. :shifty:


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## commoncenz (Aug 23, 2015)

Can't take full credit for that. I had mentioned possibly using the microwave to complete the drying process and Galaxy correctly pointed out the dangers of that method and suggested the oven and the temperature. 

Btw, if you keep an eye on it in the oven, as it starts to dry, you can break it up into a very usable powder form by folding the parchment paper and using the back of the spoon. Do this a few times each time that you check on it and breaks down nicely. Well, so far it has. I've had it in the oven for about an hour and have checked it about 3 times using the fold/spoon method to break it down each time.


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## commoncenz (Aug 23, 2015)

OK, son returned home and his camera is working. So, here is a picture of the SC I made tonight. I used Galaxy's original recipe and completely dried it in the oven. I am wondering though because Galaxy stated the theoretical yield was about 268 grams. I ended up with 290 grams. However, as far as I could tell, the citrate was as dry as could be and I was able to get it into a powdered form by using the method I described above and then using the spoon to grind it down after it was dry and "crunchy".


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## DeeAnna (Aug 24, 2015)

Nice! SC can make a hydrated form where some water is chemically bound to the main molecule. That could explain the weight difference. Another possibility is incomplete reaction so some baking soda or citric acid is left over. I vote for option 1.


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## SoapSap (Aug 24, 2015)

I just bought food grade Sodium Citrate and would like to know if I can use this in my soap as well as you it in food applications?


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## DeeAnna (Aug 24, 2015)

Yes, it will work.


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## DeeAnna (Aug 25, 2015)

Update on my sodium citrate solution: The sodium citrate solution at 33% concentration is water clear with only a faint trace of solids on the bottom of the container. The solids could easily be impurities from my food-grade baking soda and citric acid -- I was using grocery store products, not lab-quality stuff. 

A 50% concentration does not work -- not all of the SC will dissolve. I think, however, that I could have made a 40% concentration, per Patrick's info, so that's on my list to try next time. 

***

To recap what I did with a revision for the starting amount of water to use:

100 g citric acid
131 g baking soda
300 g distilled water
Plus more distilled water for dilution after the reaction is done

Find a container that a LOT larger than the total volume of your ingredients. (For this recipe, I'd use a 3 quart container.) The container should be glass, stainless steel, plastic, or porcelain-enamel coated. Do not use aluminum. (It's not going to do anything horrible if you do use aluminum, but the citric acid will react with aluminum, just like tomato sauce does, rather in addition to reacting with the baking soda.) Weigh your container and record that weight. 

Put the water into the container and dissolve the citric acid in the water. Gradually add spoonfuls of baking soda to the mixture and stir. The mixture will foam exuberantly, so add the baking soda gradually enough that you can control the foaming with stirring. 

After the baking soda is all added, the mixture will continue to fizz and foam. You will also find the container will get quite chilly, and that's okay. Stir as necessary to keep the foam from overflowing your container. Once the foaming slows down enough to stay inside your container, you can leave the mixture to fizz away on its own for several more hours. It's done when there is no more fizzing.

You may end up with a mixture of clear liquid and white solids or just a clear solution. Either way is fine. Once the mixture is fully reacted, weigh the container plus its contents and calculate the water in the mixture:
Water weight after the reaction = Total weight - Container weight - Sodium citrate weight

The theoretical sodium citrate weight for this example is 134 grams, so: 
Water weight after the reaction = Total weight - Container weight - 134 g

Add enough extra water to make a 33% (or 40%) solution, whichever you prefer. For a 33% concentration, this "Final water weight" should be about 406 g for this particular recipe. For a 40% concentration, the "Final water weight" should be 335 g.

We already have some water in the mixture (see above for "Water weight after the reaction"). Subtract this weight from your desired "Final water weight" to get the water to add to end up with the concentration you want.
Water to add = Final water weight - Water weight after the reaction

Add this extra water to the mixture. The white solids should mostly or entirely disappear. Store this sodium citrate solution in a plastic or glass bottle for use in your soap.

***

Thanks, Galaxy, for sharing your idea and your methods!


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## Dahila (Aug 26, 2015)

I am using CA for some time but I put it into water and dissolve before adding lye.   With Sodium citrate is the same? Before lye?


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## commoncenz (Aug 26, 2015)

Dahila said:


> I am using CA for some time but I put it into water and dissolve before adding lye.   With Sodium citrate is the same? Before lye?



Dahila, I was discounting enough water from my lye water to dissolve my sodium citrate and then mixing the solution into my oils before adding the lye water. I read somewhere that you could just dissolve the sodium citrate in your water before adding the lye as there shouldn't be a reaction since the sodium citrate is a byproduct of the CA/Lye reaction. (might have got that from this thread).

So, I made a batch yesterday and dissolved the sodium citrate in my water before adding the lye. No problems.


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## DeeAnna (Aug 27, 2015)

I agree w Patrick. Sodium citrate is a salt, just like sodium chloride (table salt), and some people add a bit of table salt to their recipe for hardness. Dissolve it in the water before lye.


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## Dahila (Aug 27, 2015)

thank you Patrick and DeeAnna, I thought it should be added as I had with CA, thank you so much for confirming it)


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## galaxyMLP (Aug 27, 2015)

I'm really glad so many people have been trying this and optimizing this method. I think I'm going to do it like Dee has with a 40% solution next time. It just seems to make more sense and be less of a pain.


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## The Efficacious Gentleman (Aug 27, 2015)

I'm thinking of a 25% solution, just because I want easy maths.


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## Nevada (Aug 27, 2015)

This is easy and works great! 
add .6246 gram lye for every gram of Citric acid


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## The Efficacious Gentleman (Aug 27, 2015)

Actually, Nev, the point of this method is to make the sodium citrate using baking powder and citric acid, rather than lye and citric acid - so no need to add any more lye in to the batch.


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## galaxyMLP (Aug 27, 2015)

Yes, Nev, TEG is right. I wanted to have a way to use citric acid that wouldnt involve adding extra lye. Lye (NaOH) is a pretty expensive and very strong base. Baking soda is much less expensive and just as effective in this case for neutralizing citric acid so it made sense to make up the sodium citrate in this way!


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## DeeAnna (Aug 27, 2015)

Annnnnddddd, as if Effy's and Galaxy's reasons aren't sufficient, I want to add .... many good scientists and engineers also subscribe to the theory "If it ain't broke, fix it anyways".

:mrgreen:


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## galaxyMLP (Aug 27, 2015)

Oh my gosh Dee! Isn't that the truth. I just cracked up!


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## commoncenz (Aug 27, 2015)

DeeAnna said:


> Annnnnddddd, as if Effy's and Galaxy's reasons aren't sufficient, I want to add .... many good scientists and engineers also subscribe to the theory "If it ain't broke, fix it anyways".
> 
> :mrgreen:



LMAO .. I spent 6 years in the U.S. Navy as an electronics technician. Many times we took a similar approach in order to get a little down time. Pull a module unsolder a component and replace it with a new one. Make sure to take your time so that you miss PT (physical training) that day. :shh:


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## DeeAnna (Aug 27, 2015)

I was hoping some of y'all would get the geeky humor thing.


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## Dahila (Aug 29, 2015)

Ha today was my day for Sodium Citrate,  I had copy Commoncenz  
Teresa all my pots are lagostino so no reaction to CA and BS) 
The rest of pics are the process.  I ended up with 298 g of SC.  
400 ml water weight 340 g
I made it it a fine powder so I am ready to rock,  Thank you Galaxy, DeeAnna, and Commoncenz) Next time I will make double portion .
I am going to try 2% of my total oils which will be 30 grams  (1500 g total oils) I hope I am not off with my calculation
I had done the search on Health Canada and they do not like CA but the sodium citrate is accepted) It is for Canadians , we have here


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## galaxyMLP (Aug 29, 2015)

Love it! Looks great!


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## Dahila (Aug 30, 2015)

I tried to dissolve it and it takes a moment) I hope it is sodium citrate in pure form


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## DeeAnna (Sep 14, 2015)

I was wanting to use my homemade citrate to see how citrate controls soap scum created by mixing hard water from our well with my liquid soap. I wanted to add these results to the thread I started here: http://www.soapmakingforum.com/showthread.php?t=52456 

Problem is, when I added the citrate to the water and soap solution, the citrate "broke" the soap so I ended up with scummy water that had a layer of fatty acid on the surface. Thinking perhaps I had an excess of citric acid still left in the solution, I added a bit extra baking powder to ensure the acid was fully reacted to citrate. Tried the test again. Same results. 

Added a bit of citrate solution to just the liquid soap -- no added water -- and the mixture of citrate and the (originally transparent) LS turned an opaque white.

I'm stumped. My understanding has been that citrate works pretty well to chelate metals and reduce soap scum, and I haven't been hearing people complain about citrate "breaking" their soap. 

You other soapy chemistry geeks out there -- what am I missing? Suggestions and thoughts are most appreciated.

*19 Nov 2016 update:* I found out what the problem was. Other soapers bought commercial sodium citrate and did not report any problems with their liquid soap breaking. After some thought, I realized my homemade sodium citrate solution had to have extra baking soda or citric acid in it. Either of these ingredients would have caused my soap to break. 

The solution to this problem is to add a pinch of one ingredient (say citric acid) and see if the mixture starts to fizz again. If it fizzes, then let the fizzing stop naturally, add another pinch of citric acid, let it fizz, and repeat until the last pinch causes no fizzing. 

If the mixture doesn't fizz with an added pinch of citric acid, then add a pinch of baking soda and see if that fizzes. If so, then let the fizzing stop naturally, add another pinch of baking soda, let the mixture fizz, and so on until no fizzing happens. 

The key is to not get in a hurry -- add a little bit at a time so when the fizzing finally ends, the mixture is as close to pure sodium citrate and water as possible with very little extra citric acid or baking soda. If you overshoot, you could add a bit of the other ingredient to balance things more precisely.


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## The Efficacious Gentleman (Sep 15, 2015)

I wonder if it is akin to when we try to add other things to a finished LS? If we add an EO after we make the soap paste, it doesn't always stay well mixed. Of course, that could be an oil and water problem, but the soap should act as a mild emulsifier. Maybe the key to chelating with SC is that it is in the product itself?


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## DeeAnna (Sep 15, 2015)

Perhaps you're right, Gent, but if so I'm going to have to seriously rethink my mental picture of the process. The chelating activity that reduces soap scum should occur when the soap is in solution with the water on your skin as you bathe. That process needs to happen very quickly, thus the chelants (EDTA, citrate) have to be able to mobilize fast to do their job. 

I'll do some more digging.


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## The Efficacious Gentleman (Oct 2, 2015)

DeeAnna said:


> Perhaps you're right, Gent, but if so I'm going to have to seriously rethink my mental picture of the process. The chelating activity that reduces soap scum should occur when the soap is in solution with the water on your skin as you bathe. That process needs to happen very quickly, thus the chelants (EDTA, citrate) have to be able to mobilize fast to do their job.
> 
> I'll do some more digging.



Any more joy playing with the home made SC in soaps?


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## DeeAnna (Oct 2, 2015)

Hey there, Gent -- Nope, I'm not getting any results from digging into the chemistry, nor has anyone else offered any suggestions to enlighten my ignorance. 

The only odd bit I have uncovered recently is that when Kevin Dunn did tests to find his tests of effective chelators and antioxidants for soap, he learned sodium citrate (on its own) was not at all effective in controlling color change in his test soaps. A mix of citrate and rosemary oleoresin (ROE) worked worse than ROE alone or no treatment at all. Only when citrate was added with BHT did citrate add something positive to the party. Not sure what that is telling me, but it's something.

The project is still on my to-do list, but stalled for the moment. :think:


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## kumudini (Oct 2, 2015)

Thanks for the bump folks, it reminded me that I still needed to make it. It's on my stove now, boiling away.


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## kumudini (Oct 2, 2015)

I finished making the sodium citrate and drying it to my satisfaction. I was thinking, it's too much work but it helps me save on the lye, not that it's super expensive but since I'm running out faster. Anyways, the light bulb goes off! If according to DeeAnna I need 6.24 grams of lye to neutralize 10 grams CA, it appears from Galaxy's math that I would need 13 grams of sodium bicarbonate for the same amount of CA. Why don't I just add the extra base as bicarb instead of lye and be done with it? It's just as handy as CA is in my soaping area and math is not a problem for me. So, what you say DeeAnna, can I just add 13 grams of sodium bicarbonate to every 10 grams of citric acid in my recipes?


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## commoncenz (Oct 2, 2015)

how would you make sure that the bicarb interacted with the CA and not the lye?


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## kumudini (Oct 2, 2015)

commoncenz said:


> how would you make sure that the bicarb interacted with the CA and not the lye?



Brilliant question, I'm sure I can add both CA and bicarbonate to water and wait till fizzing is done, then add the solution to the recipe. But my google search revealed that the end product of a bicarbonate and lye reaction would be the infamous soda ash, which means I absolutely have to wait until all the fizzing is gone, which hopefully means that the CO2 is out of the equation and won't cause any additional ashing.


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## DeeAnna (Oct 2, 2015)

I think your math is correct, but Patrick has cut to the heart of the matter. You'd have to wait long enough to let the citric-bicarbonate reaction to end before putting your NaOH into the mix. The citric-bicarbonate reaction is going to be a slow step, even if you add heat to drive the process. The reaction of citric acid with NaOH is going to be near instantaneous. I guess the only reason why I'd put up with doing the bicarbonate reaction as you propose is only if the cost of NaOH was as dear as unicorn horns.


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## kumudini (Oct 2, 2015)

I agree DeeAnna, after I finish this batch of sodium citrate I'm just going to use EDTA. Again, not that the lye is expensive but I don't want to run out before my next order.


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## hmlove1218 (Jan 10, 2016)

DeeAnna said:


> Galaxy's original recipe:
> 
> 400 g distilled water
> 200 g citric acid
> ...



I'm trying to wrap my brain around this as all these numbers have made my head spin lol.

1) How did you arrive at a total of 268 g SC after the reaction for above recipe?
2) After the reaction, subtract SC from total weight to get current water weight and then add water (if needed) to result in 50/50 solution, yes?  If there's too much water, just let some of the water evaporate until the correct weight?

If this has already been covered, I apologize.  I got to page 8 and my brain fizzled out lol.


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## DeeAnna (Jan 11, 2016)

1) How did you arrive at a total of 268 g SC after the reaction for above recipe?

This weight is based on translating the chemical formula for this reaction. Since some of the final product is carbon dioxide gas, some of the starting weight ends up in the air. So you can't add up the starting weights to get the ending weight. 

2) ....If there's too much water, just let some of the water evaporate until the correct weight?

If my recollection is accurate, I don't think you will have too much water if you follow Galaxy's recipe. But yes that would work to let some evaporeate.


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## galaxyMLP (Jan 11, 2016)

If you evaporate off the water and are left with a powder then you would just treat is as any dry additive and just dissolve it in the minimum amount of water and add it into your lye solution (after the lye water is prepped.). You could even add it at trace if you wanted to.

Alternatively, you can keep it as a solution. I wouldn't prep the lye water in it though since its already going to have a lot of dissolved salt in it. Thats going to make it more difficult to dissolve the sodium hydroxide in it. Just discount your water when you make your lye solution for it.

You can concentrate this solution to quite a bit more than the original solution I made. Just keep in mind that if you evaporate off too much, you'll get some sodium citrate to come out of solution once it cools. I'm not sure how much you can concentrate it b/c I haven't done it yet but, I think I might make it as a concentrated solution next time instead of the powder. I'll report back when I do. 

I'm definitely still tweaking it but, I really love using the stuff!


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## hmlove1218 (Jan 11, 2016)

Question. I mixed it up following the original recipe and something has settled out to the bottom but the rest is clear. If I shake it, it starts reacting again. Should I keep shaking it until all is dissolved?


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## galaxyMLP (Jan 11, 2016)

hmlove1218 said:


> Question. I mixed it up following the original recipe and something has settled out to the bottom but the rest is clear. If I shake it, it starts reacting again. Should I keep shaking it until all is dissolved?



Yep!! Keep going till there are no bubbles at all any more. Then, add in some baking soda (a pinch!) after its stopped fizzing when you shake it. If it starts fizzing again, add more baking soda pinch by pinch till it stops. If it doesn't fizz at all youre good to go. Thats just the easiest way to make sure all of your citric acid is reacted. The other way is to pH test it. Once you're at or above 8, you're good.


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## hmlove1218 (Jan 11, 2016)

Thanks! Don't have any pH strips, so I'll just go with the fizzy test lol


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## Gaisy59 (Nov 19, 2016)

*Sodium Citrate*



TeresaT said:


> I started to do that, but thought that would defeat the purpose of cooking it.  But, I feel better that you've made the suggestion, DeeAnna.  Thanks.  I'll go toss some distilled water in it and see what happens.  If it's a total mess-up, where do I buy sodium citrate?



Hi Theresa did anyone ever answer your question as to where you can buy sodium citrate in a store? Making your is all very well but i really dont want to if i dont have to. Chemistry was never my strong suit


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## CaraBou (Nov 19, 2016)

Gaisy59 said:


> Hi Theresa did anyone ever answer your question as to where you can buy sodium citrate in a store? Making your is all very well but i really dont want to if i dont have to. Chemistry was never my strong suit




You can order it online through eBay or Amazon - just google it. I order food grade, that way I can melt hard cheeses, too


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## The Efficacious Gentleman (Nov 20, 2016)

If you can't find it and don't want to make a big batch of it, you can add the citric acid in and calculate how much lye you need to turn it in to citrate. 

Oil weight calculates to how much citric acid you need. Amount of citric acid calculates directly to the extra lye that you need. 

It's not actually that complicated, especially if you always make the same sized batches as you only need to get the numbers once and write them down, and people here are more than willing to check your maths if you are unsure.


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## Gaisy59 (Nov 20, 2016)

*Calculating citric acid*



The Efficacious Gentleman said:


> If you can't find it and don't want to make a big batch of it, you can add the citric acid in and calculate how much lye you need to turn it in to citrate.
> 
> Oil weight calculates to how much citric acid you need. Amount of citric acid calculates directly to the extra lye that you need.
> 
> It's not actually that complicated, especially if you always make the same sized batches as you only need to get the numbers once and write them down, and people here are more than willing to check your maths if you are unsure.



Thank you very much! I have ordered the same product that Irish Las has but i will also take you up on the citric acid calculations offer. I will first find a recipe i will stick with and then ask for your assistance.


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## Dr.J (Nov 22, 2016)

Gaisy59 said:


> Hi Theresa did anyone ever answer your question as to where you can buy sodium citrate in a store? Making your is all very well but i really dont want to if i dont have to. Chemistry was never my strong suit



I've bought it on Amazon before, but ever since I found it at The Chemistry Store I buy from there exclusively.  The Chemistry Store also carries many other soaping ingredients.


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## Gaisy59 (Nov 24, 2016)

Dr.J said:


> I've bought it on Amazon before, but ever since I found it at The Chemistry Store I buy from there exclusively.  The Chemistry Store also carries many other soaping ingredients.



Awesome thanks for the info!


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## Hils67 (Aug 30, 2019)

DeeAnna said:


> Hey, Teresa, good save! After a cuppa joe this morning, I rummaged around, found my geek hat and paraphernalia, and re-read Galaxy's original post. She did all the math for us already!
> 
> Galaxy's original recipe:
> 
> ...


I know this is an old post, but thank you so much for explaining this so clearly. I was researching how to use citric acid as a chelation and came across this post...brilliant!!


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## Mobjack Bay (Nov 28, 2020)

I finally made a masterbatch of 33% sodium citrate using this method.  I decided to try it because I already have a large bag of CA that I stopped using because crystals were forming on the top of my soap, even when I dropped down to 1%.  For the MB, I used 200 g CA, 263 g of baking soda and 600 g of water.  I mixed everything at room temp and was amazed that it fizzed for at least 7 hours (at which point I went to bed). With no heat applied, I will need to let some of the water evaporate to get the SC concentration up to 33%. I settled on 33% rather than 40% to keep the math as close to brainless as possible.

eta: I’m happy to report that I’m not seeing crystals on the soaps I made with the sodium citrate MB.


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## myriad (Dec 8, 2020)

I tried the BS and CA neutralization experiment in water and wow, it does bubble for a good while!

Baking soda has to be imported into my country, so I'm curious about creating citrate from other common household bases, like washing soda and potash. (Jackie Thompson's _Liquid Soapmaking_, for example, uses potash to make citrate, but doesn't explain the math). I can't find this info anywhere on the web, can anyone help?

From the OP, if:
1 gram of citric acid is neutralized with 1.3124 grams of baking soda 

Then:
1 gram of citric acid is neutralized with ?? grams of washing soda (sodium carbonate) or
1 gram of citric acid is neutralized with ?? grams of potash (potassium carbonate)


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## LynetteO (Jul 26, 2021)




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## The_Phoenix (Jul 26, 2021)

Mobjack Bay said:


> I finally made a masterbatch of 33% sodium citrate using this method.  I decided to try it because I already have a large bag of CA that I stopped using because crystals were forming on the top of my soap, even when I dropped down to 1%.  For the MB, I used 200 g CA, 263 g of baking soda and 600 g of water.  I mixed everything at room temp and was amazed that it fizzed for at least 7 hours (at which point I went to bed). With no heat applied, I will need to let some of the water evaporate to get the SC concentration up to 33%. I settled on 33% rather than 40% to keep the math as close to brainless as possible.
> 
> eta: I’m happy to report that I’m not seeing crystals on the soaps I made with the sodium citrate MB.


Since this thread just today got a shot in the arm… 

I, too, experienced crystallization on my soap tops when I used CA and switched to SC a few minutes this ago, I want to make my own as you did.


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## Mobjack Bay (Jul 26, 2021)

The_Phoenix said:


> Since this thread just today got a shot in the arm…
> 
> I, too, experienced crystallization on my soap tops when I used CA and switched to SC a few minutes this ago, I want to make my own as you did.


I’ve made two or three batches now and it’s working well.  I just this past weekend started using 1.5% SC (based on oil weight) and didn’t get any crystals.


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## weirdchylde (Sep 27, 2021)

galaxyMLP said:


> If you evaporate off the water and are left with a powder then you would just treat is as any dry additive and just dissolve it in the minimum amount of water and add it into your lye solution (after the lye water is prepped.). You could even add it at trace if you wanted to.
> 
> Alternatively, you can keep it as a solution. I wouldn't prep the lye water in it though since its already going to have a lot of dissolved salt in it. Thats going to make it more difficult to dissolve the sodium hydroxide in it. Just discount your water when you make your lye solution for it.
> 
> ...



I wanted to clarify, @galaxyMLP, since I've never used citric acid or sodium citrate before. In @DeeAnna's writeup on Sodium/Potassium citrate powder, she mentions dissolving it in 2 x water by weight. Do I then discount that dissolving water from the total water weight as well, like you said to if we used a solution? I'm having a bit of trouble figuring that out and I've pored over this thread a few times to get my head wrapped around this new step in my soap-making.

I just moved to a village with pretty hard water and am learning as I go how to adapt! Thanks for all of this science-ing, your geek-out is a boon to all of us! 

I also have another question about adding the Sodium Citrate for my hard water situation, while keeping the soap still useful for not-so-hard water. I have friends and family where I used to live who love my soap and I don't want to make double batches with and without for just that reason. If I add sodium citrate to my soap, say around 2%, will that still be ok for those with a softer water? What would be the consequences of adding too much SC with soft water?


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## isabel.carrillo (Saturday at 5:35 AM)

galaxyMLP said:


> So, I've seen posts about sodium citrate all over the place (for chelating) and I bought myself some citric acid to add it to my soaps.
> 
> I've seen alot of people talking about adding extra lye to make their sodium citrate solution in their lye water. Since I'm forgetful when it comes to soaping, I kinda wanted to skip a math step. I wanted to make sodium citrate itself (dry powder).
> 
> ...


Hi! I found your post and have done sodium citrate =) 
Before making soap with it, I would like to test it's ph. Could anyone tell me, please, how much sodium citrate I have add to 100m of water for the test? Thank you!!!!  Isabel


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