# Using citric acid?



## Obsidian (Aug 15, 2014)

For those of you use citric acid in your soap as a chelating agent, how to you add it? 
First time I added the powder into the cool lye solution and didn't care for the chemical reaction, this time I mixed it with a little water and then added that to the lye but it still reacted more then I like.

Would it be better to dissolve it in water and add at trace?


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## IrishLass (Aug 15, 2014)

If you are going to use it as a chelating agent, I would use Sodium Citrate as opposed to citric acid (they are 2 different things). The recommended use for sodium citrate is .1% as per your oil weight.


 IrishLass


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## Obsidian (Aug 15, 2014)

I already have the citric acid though and don't really want to buy another additive. I only use it once in awhile, hoping it might help with soap scum.


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## TVivian (Aug 16, 2014)

From what I'm reading you dissolve 1 part citric acid to 4 parts water then add the mixture at 1% of your oil weight at trace. I have not tried it and now I'm anxious to. I'm assuming that adding more than 1% would neutralize the lye? Thanks for this question because I learned something new that it want to try!


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## TVivian (Aug 16, 2014)

I really hate the scum.


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## Lindy (Aug 16, 2014)

Basically what you are doing when you add citric acid to your soap is increasing your superfat because of the lye being neutralized.


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## DeeAnna (Aug 16, 2014)

Citric Acid + NaOH => Sodium citrate + H2O (water) + Heat

For the math whizzes out there: 1 g citric acid neutralizes 0.624 g NaOH
A simpler version for the rest of us: 10 g citric acid neutralizes 6 g NaOH

Figure the lye needed to saponify your fats. Decide how much citric you want to use in the soap. Figure the lye needed to neutralize the citric acid. 

Total lye to use = Lye for saponification + Lye to neutralize citric acid

I would take this approach -- Measure out the water that you want to use to make the lye solution. Mix the citric acid into this water. Add the lye slowly to the water and stir as you go. This will give you more control over the speed at which the lye and citric acid react.


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## CaraBou (Aug 16, 2014)

^^^Yep, dissolve the CA in your water first, and then add the lye.  I've only done it once, but I didn't get any fizzies, smell or color change.  

I will restate a 2-part formula I had found back then that gives the ratios simply and clearly:
10 g citric acid for every 1,000 g oils
6 g extra lye for every 10 g citric acid

My CA soap is about 2 1/2 months old -- almost time to use it.  Actually, it's my avocado soap.  I plan to retrieve it during the tragic depths of winter!


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## Obsidian (Aug 16, 2014)

CaraBou said:


> ^^^Yep, dissolve the CA in your water first, and then add the lye.  I've only done it once, but I didn't get any fizzies, smell or color change.
> 
> I will restate a 2-part formula I had found back then that gives the ratios simply and clearly:
> 10 g citric acid for every 1,000 g oils
> ...



Ok, I'll do it this way next time, thanks.

Thats the same formula I use, its simple for a math challenged person like me to figure out lol.


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## DeeAnna (Aug 16, 2014)

"...6 g extra lye for every 10 g citric acid..."

I want to add a caution about the generic use of the word "lye". In today's usage, "lye" often means NaOH, but it can also just as easily mean KOH. Depending on the mindset of the readers and how carefully they read this thread, they might possibly misinterpret and think this applies to KOH as well.

The KOH version is 8 g KOH to neutralize 10 g citric acid.


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## Lindy (Aug 16, 2014)

I have to admit to not having tried this and I am trying to wrap my head around it.  What is the purpose of adding citric acid when it is neutralizing lye?  Is there a benefit that I am missing?

 TIA


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## coffeetime (Aug 16, 2014)

The sodium citrate that is formed acts as a chelator for minerals in hard water.


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## Lindy (Aug 16, 2014)

Thanks Coffeetime


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## CaraBou (Aug 19, 2014)

Just to take it a step further for those uncertain why they might want a chelator in hard water...  to reduce soap scum and make more lather.


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## The Efficacious Gentleman (Aug 19, 2014)

Out of interest, does it help that "squeeky clean" feeling that one can get with handmade soaps in hard water?

The Admirable Lady uses citric acid when making cordials such as peppermint.  I might try 1% in the next shaving soap trial......................


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## Obsidian (Aug 19, 2014)

I haven't noticed a difference in the skin feel at all but I do see reduced soap scum which is great.


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## CaraBou (Aug 22, 2014)

Obsidian, have you noticed any improvement in lather?  I hear that the extra calcium in hard water plays a dirty switcharoo with the soap salts to produce scum and to rob the soap of lather.  I'm not sure I'll be able to tell with my CA batch b/c I don't have a control to compare it against.  Also, the recipe I used it in has all kinds of stuff going on in it (avocado, cuc, +) so I _really _have no hope of telling.  Hmmm... I should make more soap so I can assess the situation better


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## Obsidian (Aug 23, 2014)

You know, I don't really have anything to compare it to either. Both soaps I used it in are high lard specialty soaps. I should make a control batch, just to see if their is much of a difference.


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## DeeAnna (Aug 23, 2014)

"...does it help that "squeeky clean" feeling that one can get with handmade soaps in hard water?..."

"...have you noticed any improvement in lather? I hear that the extra calcium in hard water plays a dirty switcharoo with the soap salts to produce scum and to rob the soap of lather...."

Magnesium and calcium ions in hard water will react with our lovingly made sodium (or potassium) soap. The result of this reaction are calcium and magnesium soaps aka "hard water scum". These soaps are insoluble in water and an uncomfortable sticky feeling on the skin. They make the gray ring in the bathtub and rough, dull deposits in the corners of the shower. 

By adding sodium citrate, the lather and skin feel might improve or might not, depending on how hard your water is.


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## Soap Techniques (Aug 23, 2014)

Obsidian said:


> I do see reduced soap scum which is great.


 
*Obsidian*, how much citric acid (or sodium citrate) are you using?


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## DeeAnna (Aug 23, 2014)

Fata Morgana -- Your answer is in Post 9. To recap:

Carabou said:
I will restate a 2-part formula I had found back then that gives the ratios simply and clearly:
10 g citric acid for every 1,000 g oils
6 g extra lye for every 10 g citric acid

Obsidian confirmed: 
Thats the same formula I use...


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## Soap Techniques (Aug 23, 2014)

Thank you, DeeAnna! That means 1% of citric acid.


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## DeeAnna (Aug 23, 2014)

Yep, that is correct.


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## Dahila (Oct 29, 2014)

1% of CA and 0.6 % of extra lye?  Is that correct?


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## The Efficacious Gentleman (Oct 29, 2014)

Dahila said:


> 1% of CA and 0.6 % of extra lye? Is that correct?


 
I think it is safer to work out the amount (grams) of CA needed at 1% and then the amount (grams) of the chosen lye (NaOH or KOH) needed to make up for it.

So I make a 750gram batch (oil weight) which means I need 7.5grams CA, which means I need 4.5grams of extra NaOH.

Increasing our recipe lye amount by a set % does not work, as that lye amount is based on the SAP values of our oils, nothing to do with the CA.  If we have a recipe that needs more lye than another recipe and increase both by a set %, we will have different amounts of extra lye even though we use the same amount of CA.


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## DeeAnna (Oct 31, 2014)

^^^ I second what The Gent so nicely explained.


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## penelopejane (Jan 11, 2016)

CaraBou said:


> ^^^Yep, dissolve the CA in your water first, and then add the lye.
> 
> I will restate a 2-part formula I had found back then that gives the ratios simply and clearly:
> 10 g citric acid for every 1,000 g oils
> 6 g extra lye for every 10 g citric acid



Hi 

I am sorry to resurrect an old post but I don't want to rehash anything if I can help it but I just can't get this. 

Can you please tell me if CA helps with the hardness of soap?
Is it only to reduce the soap scum if you have hard water or will it help in any situation?

Thank you.


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## cmzaha (Jan 11, 2016)

This is used as a chelating agent. Here is what I do, I times my full batch weight, not just oil weight by 2.5% the resulting number gives you how much citric acid you need. Take that number and multiply it by 0.624 this will result in how much extra lye you need to add to neutralize the citric acid which results in Sodium Citrate. Where I live we have hard water and this works well for me. This is used to bind the minerals in the bath/shower water and wash them down the drain. It will not stop all soap scum but it does help and my soap lathers better. You can start out with using only 1% instead of my 2.5% and see how it works after curing. I forgot to mention I do not add this to my lye solution. I take out enough water from by needed liquid to dissolve the citric acid and dump it into my oils.


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## CaraBou (Jan 11, 2016)

Penelope, in my opinion CA does not help with hardness.  In fact I have found that if you use too much (2-3% of oils, off the top of my head) it can soften the soap. I've had two batches that I can find nothing else to blame for those troubles.  But CA can help with lather, so between that and scum, it may be worth using, especially if restrained to around 1 or 1.5%.

For hardening bars, I recommend using more oils that are hard at room temp (lard, tallow, palm, etc) and allowing a lengthy cure. If you're devoted to soft oils then consider adding salt or sodium lactate.


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## penelopejane (Jan 11, 2016)

CaraBou said:


> Penelope, in my opinion CA does not help with hardness.  In fact I have found that if you use too much (2-3% of oils, off the top of my head) it can soften the soap. I've had two batches that I can find nothing else to blame for those troubles.  But CA can help with lather, so between that and scum, it may be worth using, especially if restrained to around 1 or 1.5%.
> 
> For hardening bars, I recommend using more oils that are hard at room temp (lard, tallow, palm, etc) and allowing a lengthy cure. If you're devoted to soft oils then consider adding salt or sodium lactate.



Thanks Carabou and cmzaha I think I might just use salt.  I didn't really understand what CA was for. 
I let my dh use my 100% OO soap made with salt for the first time this week and he loved it.  He said put salt in all his soaps from now on. Not quite sure if he liked the hardness or the antibacterial qualities.


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## Savonette (Mar 13, 2016)

*lard and CA*

I love my lard-y bars and loathe the scum so I've been looking at the CA angle for a while now.  I think I found a cheater way of calculating the lye since the (1%pkgo=CA)*.65=+NaOH is just not something I can handle.  Here's my cheat.  I decrease my preferred (5%) SF by 4.5% in the SoapCalc.  I was worried that the CA% should be changed according to how much lard I use, but I see people referring to soap scum in general - not just lard scum - so I'm keeping it simple.


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## Kamahido (Mar 13, 2016)

I use Sodium Citrate so as to forgo the additional math.

Or you could make Sodium Citrate using galaxyMLP's method described following this link...

http://www.soapmakingforum.com/showthread.php?t=55723


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## penelopejane (Mar 23, 2016)

I am using CA now. Haven't made enough batches to be able to compare against the same recipe yet. 

I do find though that I can't mix it with lye. I reserve some water  to mix colours and to mix the CA etc. I add it to the oils, mix with a SB and then add the lye. This works much better for me as I like my lye to be clear.


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