No Paste, HP LS Method - Neutralization Needed?

[BrianBee]

Longtime forum lurker, first time poster. I've read and read and I don't think I've seen this answered specifically before. About me: former chemistry major, current pharmacist, and I've been making bar soap for about 2 years, and liquid soap for one year. For liquid soap, I've tried Thompson's Hot Process No Paste method (in a crockpot) as well as the Cold Process LS method that's well-described from this forum. I prefer the HP No Paste method simply because I don't have to dilute the paste afterwards; every time I've done that it's taken what seems an excessive time investment.

Using the No Paste method, every time I've neutralized with citric acid, I see a bit of separation; usually in the form of a slightly oily, white layer sitting on the top of the remainder of the clear soap, persisting from a 40% concentration through dilution down to a 20% concentration. This then requires scooping off, allowing to sit for another half-day, and repeating until the layer is no longer present.

So -- here's the question I've got. Is neutralization with citric acid even required, provided that materials are stored correctly and in good condition, calculations are done correctly, measurements are accurate, and a margin of error with a slight superfat is kept? From my chemistry background this doesn't make sense. From a common sense look at my soapmaking background, it doesn't make sense either -- or else the Cold Process LS method would require neutralization too...

Happy to post my recipe if it's felt that it's needed.

Thank you in advance!

 

[DeeAnna]

The reason why liquid soap is neutralized in some people's soap making procedures is because saponification values and alkali purity are usually estimates and not 100% accurate. If you want to ensure there is no excess alkali and no excess fat or fatty acid in the finished soap, the neutralization step is required to make that happen.

If you choose a method that does not require neutralization, then essentially you can tolerate the errors inherent in the sap values and alkali purity and you are building in a small superfat to ensure any error lies in the direction of excess fat, not excess alkali.

So ... is neutralization required. The answer depends on your tolerance for error. If you don't mind a slight superfat, then a no-neutralization method is fine. If you want a chemically "neutral" soap, however, then a neutralization method is the best way to accomplish that.

I haven't tried the no-paste method, so I can't say how a no-neutralization recipe will fare if adapted to this method. It might be worth trying a small batch to see.

 

[BrianBee]

DeeAnna, thank you for your reply. I much appreciate it.

I’m happy to give it a try! I guess my other question would be: what method would I use to test to determine whether it’s acceptably complete (for my purposes, meaning all lye is neutralized)?

Would the zap test still be reasonable (I’ve never used it on anything other than solid soaps)?

 

[Zany_in_CO]

From my NOTES:

TO NEUTRALIZE WITH CITRIC ACID

Make a 20% solution of citric acid & distilled water:
Add 2 oz. Citric Acid to 8 oz. boiling water to make 10 oz. of neutralizer.
Stir until clear.
Use 3/4 oz. (1 1/2 Tablespoons) of solution per pound of paste.

Good tips for neutralizing, lowering pH, and superfatting. Never add citric
acid powder directly into LS without first diluting it or it can throw the
soap out of solution. That results in “snow flurries” -- white flakes floating
in the soap. (This can be corrected by stirring and reheating.)

Note: I always get "snow flurries" when I add my 20% CA solution. I warm the LS to about 140°F and stir until incorporated.

Here's a link to a site that may be helpful. It was written pre-Jackie Thompson so it doesn't include the no-paste method but the info is helpful to beginners and experienced LSers alike.

http://alaiynab.blogspot.com/search/label/tutorial

 

[DeeAnna]

Yes, the zap test applies to KOH soap just like NaOH soap. Just do the test with caution, please! There's a tutorial in the "Lye based soap" forum that I recommend, if you have any questions about the method to use.