pH of the soap with pH strips?

Is any1 have experience with pH strips or pH meter with their end product, soaps? Normally what is the initial pH of the soap before pour to the mould, is the pH value will drop in line with time?

I make a soap with Oil 500g (400g olive oil, 100g coconut oil) with 65g lye dissolved in 250ml water. After homogenized and thicken it, i with pH paper , and it showed pH 12.....So is tat mean the saponification process is imcomplete...but my soap become hard on the second day? Is that after a month, the pH will drop to normal soap pH?

Any advice???

Yes- until saponification is complete, the pH wil be high. When the soap batter is still liquid or at trace, it's only about 25% to 50% saponified, depending (according to tests done by Dr. Kevin Dunn). As the soap hardens and cures, the pH will gradually drop to normal soap ranges (provided it's not a lye-heavy soap), which for lye-based soap is anywhere from 9 to 10.5 or 11. Sometimes I've seen some reported ranges as low as 8, but no matter- you can be sure it will always test out on the alkaline side of the pH scale (greater than 7). Gelled soap will reach normal ranges quicker than ungelled soap.

Most of the saponification will happen fairly quickly- in the first 24 hours or so- but the last bit (I've read estimates of 1% to 3%) happens at a slower rate due to unsaturated oils in the soap which take longer to saponify, but the last little bit gradually bottoms out around the 4th to 6th week or so as the soap cures and reacts with carbon dioxide naturally present in the ambient air.

A word about paper strips: If you find that your paper pH strips are giving you a neutral number, you can be sure that they are inaccurate. Actually, most pH strips on the market are notoriously unreliable for testing soap. That's because soap is a surfactant, and the chemicals they use in the paper strips are very sensitive to surfactants- it's like their kryptonite or something. If you want to use strips, the best kind to use for soap are the plastic kind, like these: http://www.lotioncrafter.com/ph-fix-ind ... trips.html. They are the most reliable as strips go. Paper strips are useless for accurately determining the pH of soap.

Here is a great article in regard to testing the pH of soap that all of us have found to be very helpful:

http://www.millersoap.com/phtome.html

I personally don't test my soaps for pH. Instead, I employ the 'zap test' or 'tongue test'. This will tell me if there is any unreacted lye in my soap, which is more important to me than pH in my opinion. To zap test, just wet your finger, rub it on the soap and then touch your finger to only the very tip of your tongue. If you get a zapping/stinging/prickly sensation, it's either lye heavy or just needs to cure for longer. If you get zapped, wait a few more days longer and then test again. If you find that your soap is still zapping after a week and a half has gone by, it's probably lye heavy and should be rebatched with extra oil added to it bit by bit until it ceases to zap.


IrishLass