How to deal with stearic acid

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Soaps_and_more

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Hi,

after the shaving soap I now made some make up brush cleaner soap. Both of them with high stearic acid content.

As this is a "special" ingredient I wanted to ask you for your advice, helpful hints and ideas.

It seems if you use a lot of stearic acid (30% was the highest I dared to go so far) its better not to soap too cool. Right?

The batter turned all crumbly after pouring the lye mixture in (KoH:NaoH; 60:40). That was the moment I used to put it into the shaving pots (for my first sa soap). But now I didn't have ideal containers for the brush cleaning soap and I discovered if you keep on stirring the whole thing gets quite liquid again. Heats up and gets liquid again.

So the questions would be:
soaping at higher temperatures: which ones do you use/recommend?
keep on stirring?

Would be thankful for any pointers you'd like to give.
Thank you

The recipe for the brush cleaning soap was just a simple coconut/castor/sa combination. Figured I don't need to go all conditioning and things, just cleaning.
 
High stearic soaps work best by hot process, since stearic acid is a free fatty acid, not a fat, and saponifies instantly when you add the lye -- as you noticed.
 
I wouldn't use SA in a brush cleaner formula, no need for it and it could leave a waxy residue on the brushes. I use my salt bars to clean my brushes or a 100% coconut oil soap.
 
Stearic acid makes a nearly insoluble soap. I would think you'd want a highly soluble, easy to rinse recipe for cleaning brushes -- one higher in oleic acid and/or lauric and myristic acids and lower in stearic and palmitic acids.

In any case, a recipe high in stearic acid is best made with a hot process method. Some people try to do a cold process method, but I'm skeptical given my experience.

I choose to do a two stage method with a soap of this nature. It is not strictly necessary -- just my way of handling the stearic acid so it's not so much of a pain.

Start the soap by mixing just the lye solution and the fats -- leave the melted stearic alone for a bit. This starting batter should be quite warm so when you do add the stearic acid to the mix, it won't instantly solidfy and cause stearic lumps in the finished soap. Bring the soap batter to a definite trace so you know the ingredients are at a stable emulsion. Then gradually pour and stir the stearic acid into the traced batter. It will thicken the soap quite a bit by the time all of the stearic is added. I usually stir and warm the thickened paste for 15 to 30 minutes or until a very cautious zap test tells me there's no zap. No need to cook for hours. Then scent and put the warm soap in a mold if it's a hard (NaOH) soap. If it's a soft (KOH) soap, I usually scent when warm but mold or otherwise shape the soap when cool.

"...I discovered if you keep on stirring the whole thing gets quite liquid again. Heats up and gets liquid again..."

Yes, that happens. You did a hot process method with that batch, whether you realized it or not.
 
Thank you all for your replies.
They are very helpful to me.

... and that's what I also thought thinking about the soap afterwards: I inadvertently did a hp soap. Was kinda cool :)
 

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