Sodium citrate

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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:
 
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.
 
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
 
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.
 
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.
 
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).
 
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.


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! :D (I'm such a kitchen geek).

IrishLass :)
 
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%.
 
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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