Using fats to use up excess lye in liquid soap

[poramor]

I made liquid soap with a formula I’ve used before with good results, but this time I get zapped with the soap base but I can’t pinpoint what I did wrong. My question is how can I neutralize the excess lye if I don’t know how much oil is missing. The soap is cooked but I haven't added water to disolve it yet. In an old thread

 

[poramor]

In an old thread "fixing lye heavy liquid soap," Dye Anna tought me a great solution to fix lye heavy soP that had alreadybeen dissolved and it involved adding a citric acid or borax solution. Is it a good idea to go ahead and add water to the soap base and then fix it with citric acid?

Did you zap test this soap? That will confirm whether the soap is lye heavy or not. At this point, it sounds like the soap very well might be, but if it's not, you could be fixing a problem that doesn't exist.

Since you already diluted the soap, it may be tough to add fats to use up the excess KOH. I'd probably use boric acid or citric acid to neutralize instead. If you use citric acid, remember it is very easy to over neutralize with citric acid and the neutralization process can take a bit of time, so be patient. Over neutralizing will create a whole new set of problems.

To neutralize, I'd make a solution of, oh, say about 20% citric acid in water. Neutralize a sample of the diluted soap. Scale up the dosage needed for the sample to estimate the amount of solution needed to neutralize the rest of the soap. I'd not add the whole amount of solution, however. Add 1/2 to 3/4 of what you think you need and see how that works. You can always add more acid if needed.

 

[DeeAnna]

You can neutralize the soap paste without diluting first. The other thread was about a problem with someone's diluted LS, so my answer was specific to that issue.

You can neutralize with citric acid or borax. Citric is less forgiving than borax -- it's easy to add too much -- so take your time and be patient. The upside of using citric acid is that it is not borax. Some people don't like to use borax in their products.

You can also neutralize with a fatty acid or with fats -- it's practical to do this with paste soap. It can take longer to neutralize by adding fat compared with citric or borax, but the end result is soap as opposed to sodium citrate or sodium borate.

But in the end, they all will work. Just different ways to get to the same end result -- a soap that's not lye heavy.

 

[poramor]

DeeAnna, thank you for your comment. How do I go about adding fat to the soap base? Can I add some olive oil which is tge main ingredient in the formula? What percentage of the soso base weight should I start out testing? Should I add dustiled water also?

 

[DeeAnna]

If I had a soap that I wanted to neutralize with fat, I'd probably do this --

Heat the paste until it is quite warm -- say 160-180 F / 70-80 C. The heat will help the lye and fat saponify and make the paste easier to stir. Maybe add a little water to help the paste be even easier to stir, but this isn't strictly necessary. (I've had some softer pastes that aren't hard to stir.) Add some fat and stir really well to combine. You could cover the pot and keep the paste at that temperature for perhaps 30-60 minutes, then turn off the heat and let the paste cool naturally to room temperature. After several hours to overnight, stir again, and check for zap.

The main problem is you don't exactly know how much fat you need, so fixing the soap will be a bit of a trial and error process. If the zap you got from the paste is moderate to light, I might add perhaps 1% of the total fat in the recipe and see what that does. This amount is purely a guess -- you need to add the amount that makes the most sense to you.

 

[AliOop]

I would also ask, how long has it been since you cooked this paste? If it has just been cooked, the paste may not be done saponifying.

 

[poramor]

Thank you DeeAnna and AliOop for your feedback. I used a cold process method to cook the soap base. I used the handmixer continuosly for as long as it was feasable and then covered it well and occasionaly mixed manually. It reached a nice amber color and when tested in hot water, the water remained clear. But my hands itched when handling it and it zapped my tongue. Now I am heating half of it in the crockpot and will add half of 1% of the original oil when it reaches the temperature of 170°F and will follow the directions DeeAnna suggested. Isn´t this equivalent to an after cook superfatting of 1%? Another question: Is the method of adding diluted citric acid (or borax, which I wouldn´t like to use) quicker? If I used this method, I would make a 20% solution of citric acid and add how much to the soap base to begin with?

 

[DeeAnna]

...Isn´t this equivalent to an after cook superfatting of 1%?

Yep. that's right.

...Is the method of adding diluted citric acid (or borax, which I wouldn´t like to use) quicker?

Yes, citric acid or borax will probably be quicker IF you don't add too much acid/borax -- especially the citric. If you add too much and the soap decomposes, then fixing that problem will definitely eat up any time savings.

If I used this method, I would make a 20% solution of citric acid and add how much to the soap base to begin with?

I can't answer that question because there are too many unknowns. What I do know is 10 g citric acid neutralizes 6.24 g NaOH. Perhaps this information will help you make a decision.

 

[Zany_in_CO]

The soap is cooked but I haven't added water to disolve

how long has it been since you cooked this paste? If it has just been cooked, the paste may not be done saponifying.

I agree with @AliOop. Before doing anything, I would cover it and wait 2 weeks until the paste is fully saponified, i.e., no more 'ZAP'.

NOTE: One pound of soap paste requires (approximately) 3/4 oz. or 1 1/2 tablespoons of 20% citric acid solution for neutralization. The correct amount to use depends on the type of oils, cook time, dilution rate, and other variables that affect the pH of the finished soap. As @DeeAnna said, "you need to add the amount that makes the most sense to you."

Neutralization is normally done after dilution and tested again after the 2-week sequester.

The fact that you did cold process suggests that it may be helpful to dump the paste in a crockpot, warmed to 160°F, or Oven Process warmed to 170°F. Turn both off and let set overnight.