pH question
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Kittish
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Ph strips will NOT tell you if you still have unreacted lye in your soap. All they will tell you, even if you do the actual proper solution to test, is that your soap is alkaline. Which you already know. You NEED to do zap testing.
Next time you make a batch of soap, look that fresh soap squarely in the eye and do that zap test! Get the worst of it over, since you KNOW fresh soap will zap you. Follow the instructions in the sticky- http://www.soapmakingforum.com/showthread.php?t=63199.
Now... that wasn't as bad as you were afraid it was going to be, was it? Kind of like putting your tongue across 9v battery terminals was as a kid, right? Bit weird, more surprising than painful, over and done as quick as a static shock.
kchaystack
Supporting Member
No. Test strips won't tell you if there is unreached lye.
You have to make a 1% solution of soap to distilled water. Depending on your mix of oils you could see high 9 to 12 and it be fine.
Most of the people here have zap tested. None of us have died or even been seriously injured by it. Just follow the thread on how to do it and you'll be fine.
You have to make a 1% solution of soap to distilled water. Depending on your mix of oils you could see high 9 to 12 and it be fine.
Most of the people here have zap tested. None of us have died or even been seriously injured by it. Just follow the thread on how to do it and you'll be fine.
pH is only one measurement, and it can be misleading. Some soaps will never reach pH 10 and be quite good, others can be lye heavy at pH 10 or 11 and strip your hide.
The difficulty is that pH measure the concentration of hydrogen ions in water solution, and not in soap. You must dissolve soap in water to get a proper measurement. On top of that, pH does not measure the amount of alkali present, only the hydrogen ion concentration (or lack of it, actually, at high pH), and it's the alkalinity, or amount of alkali, that is really the issue. pH 10 soap with very little alkalinity will be perfectly fine, pH 10 soap with high alkalinity will be very rough on the skin.
Unless you want to titrate the amount of alkalinity in you soap, I'd stick to the zap test, it's VERY reliable. No zap, the soap is good, if it has even a tingle, it's not safe to use.
You won't mistake the zap for anything else, and if you do it correctly even on fresh soap it's just nasty, not damaging. I don't zap test until I think the soap is completely saponified.
And don't forget that saponification and full cure are NOT the same -- with no visible changes, soap six weeks old will be much nicer than soap a week old that does not zap. Use weight loss from water evaporation to check state of cure -- usually by the time the soap stops losing water, it will be nice to use. Better if older, of course, but that's not always possible.
The difficulty is that pH measure the concentration of hydrogen ions in water solution, and not in soap. You must dissolve soap in water to get a proper measurement. On top of that, pH does not measure the amount of alkali present, only the hydrogen ion concentration (or lack of it, actually, at high pH), and it's the alkalinity, or amount of alkali, that is really the issue. pH 10 soap with very little alkalinity will be perfectly fine, pH 10 soap with high alkalinity will be very rough on the skin.
Unless you want to titrate the amount of alkalinity in you soap, I'd stick to the zap test, it's VERY reliable. No zap, the soap is good, if it has even a tingle, it's not safe to use.
You won't mistake the zap for anything else, and if you do it correctly even on fresh soap it's just nasty, not damaging. I don't zap test until I think the soap is completely saponified.
And don't forget that saponification and full cure are NOT the same -- with no visible changes, soap six weeks old will be much nicer than soap a week old that does not zap. Use weight loss from water evaporation to check state of cure -- usually by the time the soap stops losing water, it will be nice to use. Better if older, of course, but that's not always possible.
Zany_in_CO
Saponifier
Generally speaking, yes. But pH starts out high and mellows over time.
ZAP TEST: I'm not a scientist, I just know what works for me. I have not done a zap test since I first started soaping. Zap testing simply isn't necessary. To my mind at least, "Patience" is best substitute for the zap test. Meaning, if your soap requires 4-6 weeks to cure, then wait that long to test it. I like to take the scrapings from my soaping equipment after soaping and, with gloved hands, roll them into a ball and shape them. I use that soap to test the progress of the bars I have curing on the shelf. I just wash my hands, rinse and dry. If my hands hurt or sting or feel dry, I know the soap has a way to go.
pH Strips: I like using these to adjust the pH of liquid soap. I get a German brand from Lotion Crafter dot com. I find them fairly reliable as my LS tests pH 10.5 after dilution. I sometimes soap at 0% SF + 10% more KOH, so I then use 20% citric acid solution to lower the pH. I prefer the feel of the LS after adding a bit (0.06%) citric acid solution.
Phenolphthalein (10%) solution: I've found this to be reliable, not for testing pH, but for knowing when the LS paste is ready for dilution. It is particularly helpful when I make GLS. The paste goes through all the phases of becoming soap in 2-5 minutes and is quite hot at the end. After it sets for an hour, I stick a knife into the center, pull it out, add a drop of Pheno to the blade and it usually test clear, which tells me it is ready for dilution. If it tests pink, I wait another hour. NOTE: One time I tested every day for 3 days. On the fourth day, the Pheno drop miraculously tested clear! YAY! So I diluted it at that point and it was crystal clear. Not sure what happened there, but happy that it worked.
I'm not saying "Do what I do" to anyone. Just sharing what works for me.
