Citric acid as Chelant

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cmzaha

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figured I would start a new thread with this question. Has anyone noticed Crystallizing on the outside of soap when using Citric Acid + Lye for chelating? I had been noticing many of my soap have small crystals and sure enough every one was when I was using CA. I have since changed to EDTA with no crystallizing. Just curious.
 

penelopejane

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figured I would start a new thread with this question. Has anyone noticed Crystallizing on the outside of soap when using Citric Acid + Lye for chelating? I had been noticing many of my soap have small crystals and sure enough every one was when I was using CA. I have since changed to EDTA with no crystallizing. Just curious.
I have been using CA for the last few months and haven't had any crystalising.
I don't mix it with the lye though.
I mix it with reserved water from the batch and sometimes mix table salt with it when it has dissolved.
I then SB these into the oils and then add the lye.
I don't know if that makes a difference or not but I haven't had the crystals.
I have not used EDTA.

I am not sure what CA brings to a soap. It's supposed to stop soap scum. Not sure if it does.

I have discovered though that you can't use CA with Goats milk. It makes the bar really soft!
 
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TeresaT

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figured I would start a new thread with this question. Has anyone noticed Crystallizing on the outside of soap when using Citric Acid + Lye for chelating? I had been noticing many of my soap have small crystals and sure enough every one was when I was using CA. I have since changed to EDTA with no crystallizing. Just curious.
No, I didn't get any of that. I used CA for several batches (I had about a pound of it) before I switched to SC. I got tired of adding the extra NaOH each time I made the soap because I use premixed solution. I've recently switched to EDTA, but haven't used any of those bars yet. I'm still working on my CA & SC supply of soap.

I know that "nothing" dissolves in the lye solution. I found that out the hard way and all of the additives that needed to be dissolved went into the water before the NaOH was added. When I add something to the water, I always stir until the water is clear. Again, I learned the hard way that if I don't do that, I end up with syrup at the bottom of my lye solution that has to be filtered through a fine mesh sieve. (It looks like that nasty sludge you get at the bottom of your cup when you put too much sugar in your tea or coffee. Not that I've ever done that...)

Hmmm, I wonder why you ended up with the crystals. Curiouser and curiouser!

I have been using CA for the last few months and haven't had any crystalising.
I don't mix it with the lye though.
I mix it with reserved water from the batch and sometimes mix table salt with it when it has dissolved.
I then SB these into the oils and then add the lye.
I don't know if that makes a difference or not but I haven't had the crystals.
I have not used EDTA.

I am not sure what CA brings to a soap. It's supposed to stop soap scum. Not sure if it does.

I have discovered though that you can't use CA with Goats milk. It makes the bar really soft!

It does work. I have really hard water and had horrible soap scum when I first started making soap. My hair sheds almost as bad as a dog does. Between my hair and the soap scum, my shower was horribly clogged. It was pretty gross. I almost quit using home made soap. However, the soap scum was reduced when I added the CA to the recipe. I don't usually use milks in my soap, but I wouldn't think the CA should effect the hardness of the bar when you're using them as long as you remember to add the extra NaOH to the recipe. For every 10 grams of CA you use, you have to add 6.24 grams of NaOH. If you don't do that, you'll end up with a higher SF. I would imagine you'd get a much softer bar if you use milks because of the fats they contain.

You can tell the CA is working to reduce the scum by cleaning out the tub/shower to remove any/all traces of soap scum, then use a non-chelated soap exclusively and determine how long it takes the soap scum to build up. (In my house, it's about two weeks because I'm the only one here.) Then scrub the tub/shower again and use a chelated soap exclusively until the soap scum builds up. Compare the two time frames. The chelated soap should not produce soap scum build up as quickly as the non-chelated soap. However, it's a moot point if you have soft water. There shouldn't be any minerals for the chelant to bind to and wash down the drain (or leave soap scum in the first place).
 

penelopejane

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^^^^
Hi Teresa,
I am not sure if we have hard or soft water.

My hair is falling out too but I'm sickly. :)
I always add the extra lye to counter the CA. It's easy for me because I don't master batch.
The only thing I add to the water before lye is silk. I reserve water to dissolve everything else and then mix them into the oils before the lye/water solution.

Thanks to your graphic description (and a discussion with DH) I realise the CA has worked against scum. We have a 2m shower grate that I used to have to clean once a week without fail. Now I leave it much longer and it's still no where near as bad - so it does work for that.

I have just completed an audit of my soaps (45+) and have a variety of soaps to compare and I am as pretty sure that CA and goats milk don't mix. They make a very, very soft bar every time I have tried it.
Coconut milk and CA is fine!

Not sure if that helps cmzaha, though.
 
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lionprincess00

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I am not sure if this is the same thing, but I use 2% ppo sodium citrate. Well one soap I accidentally used 5% sc. I saved one soap (it was made April 2015). I picked it up a couple months ago and used it (so it was a little over a yr old). It had a grainy exterior that had a crystalline like substance come off (like fine salt, but not scratchy). Looked back at my notes and saw I used more sc than typical. I am not sure if it is the same thing as yours but thought I'd share. It (the crystals) did not zap, and once I used about half the soap, it stopped doing it. It was almost like these, crystal things, worked their way towards the surface as it cured.

Edit, maybe you were using a higher rate ppo than typical? Not sure, but will throw it out there.
 
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DeeAnna

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I was going to mention the same thing as Lionprincess.

I think you have used around 3% citric acid in your soaps, Carolyn? If so, that higher dose might be the reason why you're seeing the crystals and others are not -- I think most people use CA at a 2% or lower.

In reading old soap making manuals, the authors sometimes warn about putting too much of various salts (sodium carbonate/washing soda, for example) when making a "filled" soap. The washing soda added cheap bulk to reduce the cost of the soap and added some detergency, so soap makers liked to add it for those reasons. Problem is that salts like washing soda tend to crystallize out on the surface of the bars as the soap ages. This might also be true for sodium citrate.
 

The Efficacious Gentleman

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I think I also use 2% ca. People use 3% edta, but as we are combining ca and NaOH to make the sc, (so many acronyms!) it is not the same as using 2% sc when we use 2% ca and extra lye
 

cmzaha

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I was going to mention the same thing as Lionprincess.

I think you have used around 3% citric acid in your soaps, Carolyn? If so, that higher dose might be the reason why you're seeing the crystals and others are not -- I think most people use CA at a 2% or lower.

In reading old soap making manuals, the authors sometimes warn about putting too much of various salts (sodium carbonate/washing soda, for example) when making a "filled" soap. The washing soda added cheap bulk to reduce the cost of the soap and added some detergency, so soap makers liked to add it for those reasons. Problem is that salts like washing soda tend to crystallize out on the surface of the bars as the soap ages. This might also be true for sodium citrate.
My citric acid was used as a 50/50 solution so was well dissolved. You are correct DeeAnna I was using 3% of oil weight not total batch weight, after noticing the crystals forming, which I had no doubt was the Citric Acid, I cut back to 2% and found crystals still forming on some of the older soaps, but not all. So possibly there are other factors contributing to the crystallizing other than just CA percentage such as lye concentration or fatty acid profile. Now we know one of the issues with using higher CA. I had originally started out with 1.5% but it did not help much with the scum so I increased it until I found the % that helped, which apparently was to much. One of these days I will go back to pulling out all the recipes and compare. Since I do sell I carry a large stock of soaps and there are always some that are slow to non sellers it is the older 8 months + soaps that form the crystals. It does not affect the inside, only the outside and does wash off fine, but I am not about to unwrap, wash and relabel every soap so I changed to EDTA and do not seem to be having the problem, although I am only 6 months down the road with the oldest EDTA soap. I really think the EDTA is helping a bit better than the 2% CA as far as soap scum, but that could be just me convincing myself :)

Yes, LionPrincess it sounds exactly like what was happening to mine
 
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TeresaT

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My citric acid was used as a 50/50 solution so was well dissolved. You are correct DeeAnna I was using 3% of oil weight not total batch weight, after noticing the crystals forming, which I had no doubt was the Citric Acid, I cut back to 2% and found crystals still forming on some of the older soaps, but not all. So possibly there are other factors contributing to the crystallizing other than just CA percentage such as lye concentration or fatty acid profile. Now we know one of the issues with using higher CA. I had originally started out with 1.5% but it did not help much with the scum so I increased it until I found the % that helped, which apparently was to much. One of these days I will go back to pulling out all the recipes and compare. Since I do sell I carry a large stock of soaps and there are always some that are slow to non sellers it is the older 8 months + soaps that form the crystals. It does not affect the inside, only the outside and does wash off fine, but I am not about to unwrap, wash and relabel every soap so I changed to EDTA and do not seem to be having the problem, although I am only 6 months down the road with the oldest EDTA soap. I really think the EDTA is helping a bit better than the 2% CA as far as soap scum, but that could be just me convincing myself :)

Yes, LionPrincess it sounds exactly like what was happening to mine
Not your imagination at all. I posted a long and boring comment about EDTA in this thread (http://www.soapmakingforum.com/showthread.php?t=59839). I have used CA, SC and EDTA. EDTA wins by a mile at reducing soap scum and increasing bubbles. Because I have such hard water, I like to scrub the tub each time I use anyone else's soap or if I'm using a new soap of mine that I've made changes in the recipe. Then use that soap exclusively to check for scum build up. Not exactly scientific research, but it's real world research and that works for me. I don't want to give (or eventually sell) soap to someone and have them complain about the scum in their tubs.
 

penelopejane

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I use CA at 1% of oil weight. 10g of CA per 1000g of oil.
This is a little different from Sodium Citrate but it's used at a little higher rate than CA.

After reading Teresa's report on soap scum I realise that it is making a difference to my soap. It doesn't seem like you have to use much. Apparently my water is not hard but my DH says the CA makes a difference and the drain cleaner (me) seems to agree. :)
 
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