Hydroxide Issues + Shaving Cream Recipes

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Apr 6, 2014
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Hi everyone,

New to the soap making process (4 batches in). Making the following recipe with both KOH and NaOH:
5% Avacado Oil
5% Coconut Oil
10% Castor Oil
30% Palm Oil
50% Stearic Acid

I tried a similar recipe last go round, but I keep getting too base (purple colour on the pH strips rather than the green). For 0.2 pounds of soap, what amounts of hydroxide do most people recommend?

What other reasons are there for getting purple (too much of a base)? Does the amount of time make a difference (i.e. more than an hour and 15 min)? Other variables?

I would really appreciate thoughts on this matter

I'm not a big pH tester, but I don't think you'll ever get a lye-based soap to show as green on the strips and still be a usable soap!

A lot of people suggest making a minimum of 2 pounds of soap to allow for errors in measuring. A few grams over or under the target when making 2 pounds is less dangerous than a few grams out in a 0.2 pound batch!

http://www.soapcalc.net/calc/SoapCalcWP.asp here is a soap calc that allows you to put in your recipe, batch size and so on and it will work out the lye. If you want to do a mix of K and Na then you'll need to work out the total amount of each for the oils and then use the maths to work out the % of each. K and Na amounts are different, so you can't replace 50 grams of Na for 50 grams of K - it doesn't work like that.

As it is, for a 2 pound batch using the above oils at a 5% superfat, you'll need 122.192 grams of NaOH.

If you are making it using cold process, it will take some time for it to fully saponify (lye and oils to combine) so I would not test it in any way until after a good 24 hours at the very least.
Thanks for the response.

And yes, I have been playing with the soap calc. tool. As for the different hydroxides, I will select NaOH and get the amounts. Then I will select KOH and get the amounts and from there place a weighting on each. I believe that is what you are referring too.

I have made a batch where we did get green on the pH strip. But doesn't that make sense? Shouldn't all green mean that the soap has completely soaponified and the lye no longer remains?

And yes, only reason I am doing 0.2 pounds is to cut down on ingrediants especially since I am still trying to find the right recipe. Using 2 pounds batches, althought quite large, may be something I will need to consider going forward.

The pH of soap is still alkaline even after saponification is complete. That's for solid soaps. Liquid is a different beast but I don't have any experience with liquid so I'll leave that for someone else.
I've typed and deleted many answers here, just because other people can explain it better than I can.

But think of a small spider (the oils) and a giant squid (the lye). Both have 8 limbs and when they combine together there are no spare limbs floating around looking to join with anything. It's the spare limbs that are dangerous, rather than just the size of things. So even though all the limbs are safely joined with the spider, we still have a giant squid which we can't help but see.

When oils are lye are combined, the chemical "limbs" join together so that, even though the result is still alkaline because of our giant lye, it is okay. But you have to make sure that you use enough oil to bind with the lye.
I would not make that small of a batch. A 1 lb batch minimum but I would start with 2 lbs. Too much room for error especially when just starting out. PH of soap is 8-10 and some are higher. PH strips are not that accurate for testing soap.
That looks like a cream soap recipe since it has 50% stearic acid and used both KOH and NaOH - what type of soap are you trying to make with this formulation?
Liquid soaps are also alkaline. I still zap test my bars when I cut them around 24 hours after pouring. That is my certain-sure test for skin safety. I use my pH meter only on my liquid soaps to avoid burning my tongue(again). For some reason, I can't recall that soap that is cooked in a slow cooker is HOT! I aim for a pH under 10, or at least really close.

For a really new soaper, you are awfully adventurous! I still don't feel comfortable trying cream soaps due to the preservatives needed, and the skill level is a bit out of my reach at the moment.(I have been soaping since last summer, and have made both bar and liquid soaps.)

Oh, and I totally agree with the 1 pound of oils minimum size batches. Any smaller, and every 10th of a gram makes too large a difference.
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From what I understand(and I am no expert), a soap product that is brought down to pH of 7 is prone to separating out and becoming un-soap. I also have high doubts as to the efficacy of such a thing, as soap's mechanism of action is that the alkalinity "tears apart" the acidic bond between dirt and the oil on skin.

So the recipe that it created turned out quite well. It is a shaving soap (hard). Not as hard as those found commercially, but not as soft as the cream based shaving creams.

Lathered quite well. Thick. Not too bubbly. Slightly creamy. Only thing I am worried about is the zap test. Tough to tell if I am being zapped, or if it is simply too hot (since it is being cooked in a crock pot).

PH turns out to be a darker green. So about a 9-10.
If you are really interested in cream soap there is a cream soap group on yahoo which is great for beginners. I was a member there but ended up leaving as I didn't fit in... LOL

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