# Sodium citrate



## Sonya-m (Jan 29, 2015)

I ordered some to use to counter the effects of the slightly hard water in my area

It's arrived today, the bag says trisodium citrate with a CAS of 6132-04-3 which when googled is trisodium citrate dihydrate

Is this the right thing?


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## The Efficacious Gentleman (Jan 29, 2015)

If it turns out to be the wrong stuff, can you get citric acid?  You can buy it over here for cooking and then you increase the lye a touch as the lye turns it in to sodium citrate.


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## Sonya-m (Jan 29, 2015)

I haven't looked yet but am assuming I can. I went for the citrate to avoid having to increase the lye (I know it wouldn't have been hard, I just want to make it as easy as poss)


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## Susie (Jan 29, 2015)

Look in the canning supplies for citric acid.  That's where I find it here.


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## Saponista (Jan 29, 2015)

I've searched but I can't find the saponification value for citric acid anywhere. Someone wrote on another forum it was 0.571 oz lye per oz citric acid monohydrate, but I am used to using grams so am a bit confused. I think it would be the same, 0.571g lye per g CA but I'm unsure as I see imperial measurements and begin to panic!


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## Sonya-m (Jan 29, 2015)

Thanks everyone. DeeAnna confirmed on another thread for every 10g of citric acid I would need 6g extra lye but also confirmed I can used sodium citrate instead as this is just the byproduct of lye+citric acid so no need to alter my lye number

Just wanting to confirm this sodium citrate dihydrate is the correct thing


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## The Efficacious Gentleman (Jan 29, 2015)

Sonya-m said:


> Thanks everyone. DeeAnna confirmed on another thread for every 10g of citric acid I would need 6g extra lye but also confirmed I can used sodium citrate instead as this is just the byproduct of lye+citric acid so no need to alter my lye number
> 
> Just wanting to confirm this sodium citrate dihydrate is the correct thing


 
Aye, which is why my post said that IF it isn't the right stuff and you want sodium citrate, you can use the acid and more lye.................


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## Sonya-m (Jan 29, 2015)

The Efficacious Gentleman said:


> Aye, which is why my post said that IF it isn't the right stuff and you want sodium citrate, you can use the acid and more lye.................




Sorry, I didn't mean to imply you didn't know sodium citrate could be used instead


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## The Efficacious Gentleman (Jan 29, 2015)

No worries

I did some digging - trisodium citrate dihydrate is a chelator, and I also found this - 

http://www.jungbunzlauer.com/en/products/citrics/trisodium-citrate-dihydrate.html


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## Sonya-m (Jan 29, 2015)

Thanks - I guess I will give it a go in that case.


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## SoapBro (Jan 29, 2015)

as stated before, trisodium citrate is the right stuff, i use it in every soap.


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## RhondaJ (Jan 29, 2015)

SoapBro said:


> as stated before, trisodium citrate is the right stuff, i use it in every soap.



at what ratio is this used in soap to fight the soap scum in hard water?


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## nframe (Jan 29, 2015)

SoapBro said:


> as stated before, trisodium citrate is the right stuff, i use it in every soap.



Why do you use it in every soap?  What benefits does it bring?  And, lastly, how much do you use?  This is very intriguing...


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## The Efficacious Gentleman (Jan 29, 2015)

I use citric acid and more lye (so I technically use sodium citrate) rather than the trisodium citrate, but it helps to improve lather in hard water and reduce soap scum


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## nframe (Jan 29, 2015)

The Efficacious Gentleman said:


> I use citric acid and more lye (so I technically use sodium citrate) rather than the trisodium citrate, but it helps to improve lather in hard water and reduce soap scum



How much citric acid do you use?  10g ppo and an extra 6g of lye?


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## The Efficacious Gentleman (Jan 29, 2015)

Need to check my notes but I think it's 10g per 1000g oil - so 1% of oil weight.  Plus 6g of lye per 10g of citric acid.  That took some measuring when I was making 50g batches of shaving soap trials............................


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## DeeAnna (Jan 29, 2015)

"...saponification value for citric acid..."

It doesn't have a saponification value, so you will never find that information. The only chemicals that have sap values are the ones that make soap. Citric acid doesn't make soap.

Trisodium citrate dihydrate is what you want. This is the full technical name. The "common name" for this chemical is just sodium citrate.

If you are using sodium citrate, then NO extra lye is needed. 

If you are using citric acid, then you need 6 g extra NaOH for every 10 g of citric acid. Or 6 oz extra NaOH for every 10 ounces of citric acid. However you say it, it means exactly the same proportion of lye to acid.

Yes, the precise number is different than this, but you'd need a lab quality scale to measure out the extra decimal places, so forgeddabout it. Rounding to 6 g is good enough for our kitchen chemistry.


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## Sonya-m (Jan 29, 2015)

Excellent! Thank you everyone! Glad it's the right thing, wasn't expensive either, 1kg for £1.89 plus £2.89 postage. I don't know if this is a good price or not

Another question now - do I add this to my water before I add my lye and let is dissolve before adding the lye?

Does it have any impact on trace times?


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## Saponista (Jan 29, 2015)

Thanks DeeAnna  

Do you find it really makes a difference EG? I have very soft water so don't have trouble with lather and scum but my parents have hard water and I want to make something that will work better for them too.


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## nframe (Jan 29, 2015)

Sonya-m said:


> Excellent! Thank you everyone! Glad it's the right thing, wasn't expensive either, 1kg for £1.89 plus £2.89 postage. I don't know if this is a good price or not



Where did you buy this?


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## Sonya-m (Jan 29, 2015)

nframe said:


> Where did you buy this?




http://m.ebay.co.uk/itm/like/161103...1=ICEP3.0.0-L&ff12=67&ff13=80&ff14=108&ff19=0


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## SoapBro (Jan 29, 2015)

RhondaJ said:


> at what ratio is this used in soap to fight the soap scum in hard water?



well i have very hard water and recently i've been experimenting with the dosage and what i've discovered is that you can go as high as 3% of total oil weight as long as your recipe has at least 50% hard oils, if its mostly soft oils then you can do 1%-2%.

i wouldn't go over 3% even in a very hard oil soap, its probably just a waste at that point and 3% cuts scum considerably. :razz:


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## Sonya-m (Jan 29, 2015)

I'm going to start with 0.5% total weight of oils as per DeeAnna's advice in the other thread:  

Gunky drains http://www.soapmakingforum.com/showthread.php?t=51719


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## nframe (Jan 29, 2015)

Sonya-m said:


> http://m.ebay.co.uk/itm/like/161103...1=ICEP3.0.0-L&ff12=67&ff13=80&ff14=108&ff19=0


Thanks a lot.


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## DeeAnna (Jan 29, 2015)

"...do I add this to my water before I add my lye and let it dissolve before adding the lye?..."

Yep!


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## Soapsense (Jan 30, 2015)

Where in the US can you buy Sodium Citrate? I have extremely hard water.


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## Jan Johnson (Jan 30, 2015)

Hi! I bought a very nice, food grade sodium citrate from Will Powder in Florida. As SoapBro said, be careful about how much you use. I used it at 3% in my formula that is more soft oils than hard and had a problem. It precipitated out and made a hard, crusty, salty coating to my soap. Kinda like a salt bar! I was able to plane it off, but I would recommend taking Bro’s advice on the amount you use.


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## DeeAnna (Jan 30, 2015)

Soapsense -- Citric acid is indeed easier to find on the market than sodium citrate. That's why a lot of folks just use citric acid plus the extra lye needed, rather than hunt up sodium citrate.

You can often find small amounts of citric acid in hardware or grocery stores, especially in summer. Look in the section where food canning supplies are sold. It's going to be the acid one adds to canned tomatoes. (NOT Fruit Fresh -- that's ascorbic acid and will not work!)

That said, some suppliers of lotion and soapmaking ingredients do carry sodium citrate. Lotioncrafter: http://www.lotioncrafter.com/sodium-citrate.html


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## Soapsense (Jan 30, 2015)

Thanks DeeAnna, I actually have Citric acid for bath bombs.  Thought if it was easy to get the sodium citrate, it would be the easiest way for me,  Always looking for the easy route, lol.


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## cmzaha (Jan 30, 2015)

Once you get used to using the citric acid it will just become a habit to add it. I do find it easiest when using the same batch size all the time. I use 50/50 batched lye and made up a jar of 50/50 citric acid  which is already dissolved. I always use 11 grams citric acid (the 50/50 solution doubles to 22 grams) which I add in straight to my oils. I always hated how the citric acid reacted to my lye solution. After figuring out my lye in grams I add 7 grams (.624 lye x 11 =6.86 rounded up to 7)  to the number (then double this number for my 50/50 solution). Hopefully that did not add more confusion, but I just had to come up with a way to not add it to my lye solution. 
I assume this method works since it has cut the scum noticeably or it is a figment of my imagination and citric and lye have to be combined to form the chelating factor. DeeAnna can probably answer this.


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## DeeAnna (Jan 30, 2015)

The citric acid will be very good at scrounging the lye it needs, whether you mix the acid into the water that you use for your lye solution or add the citric to the oils or at trace or whatever. 

Even if you add citric acid to HP soap or rebatched soap, the acid is powerful enough to bump the sodium off a soap molecule and react with that. The result is sodium citrate and a free fatty acid (aka more superfat).


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## nframe (Jan 31, 2015)

Sonya-m said:


> I'm going to start with 0.5% total weight of oils as per DeeAnna's advice in the other thread:
> 
> Gunky drains http://www.soapmakingforum.com/showthread.php?t=51719



Hi Sonya,

Have you tried it yet?  Don't forget to let us know the results...  With pictures of course!  Thanks.


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## Sonya-m (Jan 31, 2015)

Not yet, unfortunately I have cakes to bake this weekend which are taking priority - over soap!!


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## SoapBro (Feb 2, 2015)

If anyone is still looking for sodium citrate, i actually found mine in a molecular cooking supply store,

after a very quick google, the first 4 results:
http://www.modernistpantry.com/sodium-citrate.html
http://store.molecularrecipes.com/sodium-citrate/
http://www.creamsupplies.co.uk/index.php?act=viewProd&productId=1297
http://www.shopchefrubber.com/Sodium-Citrate-100g/

in general molecular cooking supple stores are a great place to find all sorts of food grade specialty ingredients.


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## IrishLass (Feb 2, 2015)

SoapBro said:


> If anyone is still looking for sodium citrate, i actually found mine in a molecular cooking supply store,
> 
> after a very quick google, the first 4 results:
> http://www.modernistpantry.com/sodium-citrate.html
> ...


 

Oh my goodness! Where have these sites been all my life! I had no idea such places existed! Looks like I'll be doing some extra reading tonight! Thank you for posting these!   (I'm such a kitchen geek).

IrishLass


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## Sonya-m (Mar 1, 2015)

I tried my 2 week old CP (always use my bars at 1 week, 2 week etc to see how they change) with sodium citrate in today. 

There's definitely more lather than I usually get at this age but I still have floating soap scum - I assume I'm right in saying this won't change the older this soap gets?

So next time I'm going to use 1.5% total weight of oils. This was just 0.5%.


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## DeeAnna (Mar 1, 2015)

Sonya -- I suppose the soap scum issue might change as the soap cures, but I truly think it won't. Yes, I'd increase the sodium citrate dosage next batch. I think you have plenty of room for doing that -- my notes say the typical dosage is up to 3% by weight of oils. 

If 3% doesn't work, you could try higher than that, or you could experiment with another chelator like tetrasodium ETDA. I'm not sure what horrible thing will happen if one goes over 3% of citric acid -- but certainly nothing will blow up or catch fire or anything truly unsafe.  My guess is the soap may remain overly soft or have other quality problems. But I haven't tried it to know for sure.

edit: Someone in a related thread asked about adding sodium citrate when rebatching soap. I said ... Yes, I do think you could add sodium citrate in a rebatch. If you're using actual sodium citrate powder rather than making it from citric acid and NaOH, I'd dissolve the powder in some of the liquid you plan to add to the rebatch, rather than add it directly to the soap.... See: http://www.soapmakingforum.com/showthread.php?p=497360


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## Sonya-m (Mar 1, 2015)

Thanks DeeAnna - will go with a higher % next time


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