Cureing, Testing, Ph Questions

HorseCreek · Dec 22, 2016

First question, does anyone have a link to any study/ies done on curing cp and HP soap? Studies that test for loss of weight, ph, and bar hardness?

Second question, and this may be one for chemistry gurus, what is the best/most accurate way to test the ph of bar soap? Explanation or link to step by step process and equipment needed?

I want to do some experimenting!
Thanks!

topofmurrayhill · Dec 22, 2016

HorseCreek said:
First question, does anyone have a link to any study/ies done on curing cp and HP soap? Studies that test for loss of weight, ph, and bar hardness?

Second question, and this may be one for chemistry gurus, what is the best/most accurate way to test the ph of bar soap? Explanation or link to step by step process and equipment needed?

I want to do some experimenting!
Thanks!

Everything you asked for (except HP) is in Scientific Soapmaking by Kevin Dunn.

The Efficacious Gentleman · Dec 23, 2016

And part of that is because it might not be too easy to scientifically measure cure. Sure, you can measure water loss, but after a few months a Castile would not lose more water - and yet the difference between a 3 month and a 12 month Castile is huge. Albeit hard to objectively quantify.

I agree on the above - for what you asked, that book is the answer

earlene · Dec 23, 2016

Kevin Dunn's book is a very good resource for anyone interested in the chemistry of the art of soapmaking. It can give you some guidelines for your own experimentation, as well as point you in the direction of what supplies to purchase for measuring. He does have a chapter on the tools you need and the kind of record keeping one should do for quality control and experimentation.

To start with, you can weigh your soap and record water loss (weight loss) using a good digital scale that measures in at least 0.1 grams. Weigh the soap weekly to start, then when it looks like it has stopped loosing weight, drop it down to monthly. I have seen weight loss in some of my soaps months after they seemed to stop losing weight.

There is a tool one can purchase to press into the soap that tests for hardness (how much pressure it takes to make an indentation in the soap using this tool.) It's called a penetrometer and topofmurrayhill has posted about using it for testing soaps here in this thread as well as others. Kevin Dunn apparently also uses a penetrometer as he mentioned it at a lecture I recently attended. The cheapest one I have seen is about $50.00 but perhaps someone who actually has one could comment on whether or not it is a worthwhile purchase.

Dr.J · Jan 2, 2017

I too recommend that you obtain a copy of Scientific Soapmaking.

You can see some of the work that went into this book in the various lectures that Prof. Dunn has given over the years, here. A good "sneak preview" while you're waiting for the book to arrive.