Adjusting pH of liquid soap

[Traumabrew]

Hello

I made a batch of liquid soap and I want to lower the pH to be more neutral. I know you can only go so far because at a low pH, you start to destabilize the soap. But I wanted to get the soap close to 7.0 as I can.

Has anyone used citric acid to lower the pH of soap and if so, how did yuou add it? Did you make a solution first then slowly add it all the time checking the pH? If a solution is used, what is the best dilution/concentration to use?

Thank You

 

[toxikon]

Here's a good read for ya! http://alaiynab.blogspot.ca/2015/05/ph-testing-of-liquid-soap-and-lowering.html

 

[Zany_in_CO]

This is one of the FAQ's about LS that deserves a Sticky in the Liquid Soap Forum.

Bacteria shun alkaline environments above pH 9. Liquid Soaps fall between 9.5 and 10 pH. Unless you over acidify with citric acid or lower pH with something like cream of tartar, no preservative is necessary. (Failor page 12)

That means, if you lower the pH to 7, you will be inviting nasties that thrive at pH 7 (and lower) and will then require a preservative. Since preservatives are designed for lotions and the like, and there is no preservative designed specifically for LS, you'll be "playing with fire" trying to produce a safe product because some preservatives attract things like formaldehyde over time when added to LS.

That being said, I use 20% citric acid solution at a rate of 0.06% in finished LS as a chelator to help stabilize the solution and to prevent soap scum. If your idea is to lower pH to create a milder LS, that can be accomplished by finding the right balance of oils/fats/butters to suit your skin's preference.

HTH :bunny:
​

 

[Susie]

The real question is why you would want to lower the pH. It is perfectly safe for skin as long as there is no free lye in it. Use a good recipe with a zero or above superfat, then use a good scale to weigh everything carefully. Then zap test. Et voila! Safe soap!