Ph red cabbage test

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Jul 23, 2015
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I was running the ph test using red cabbage on 3 of my soaps today. If it turns green it's lye heavy and if it turns blue it is balanced. Mine turned a blue-green... Do you think it's safe to use? ImageUploadedBySoap Making1441746874.717917.jpg

(The one in the middle is greener than the picture shows.)
Hi Lucecp!

Have you zap-tested the soaps? That's a much more reliable indicator of whether or not a soap is safe to use. A soap can have as high of a pH of 12.35 and still be safe (Jonson's Baby Oat soap has a pH 12.35 for example according to a test carried out by a dermatologic study and mentioned in the book, 'Scientific Soapmaking').

Unlike a pH test, a zap test will immediately tell you if your soap has any unreacted lye in it.

For what it's worth, here's the color chart that I have in my notes in regards to the Red Cabbage Juice test:

pH 1-2 pink (acid)
pH 3-4 dark red (acid)
pH 5-6 violet (acid)
pH 7-8 Blue (neutral to base)
pH 9-10 blue-green (base)
pH 11-12 greenish yellow (base)

Since lye-based soap is alkaline, it will always test out on the alkaline side of the pH scale (most soaps fall somewhere between 9 and 11.5), which with the cabbage test can show up as blue or green or any combination two, with maybe even a little yellow thrown in at times. While the test is good for telling you whether a substance is an acid or a base, it really won't tell you if your soap is safe to use. At most, it will tell your soap is alkaline, but that's something we already know since lye-based soap by definition is an alkali salt of a fatty acid.

I recommend doing the zap test instead.

IrishLass :)
I raise a lot of purple cabbage in my gardens. Didn't know you could use it in soap making/testing
This is not directed against you, MM, please don't take it that way. I just never understand why people don't zap test for safety. It is so easy, free, and much more idiot-proof (tested against me!) than anything else ...
I cannot begin to imagine how gross that smelled. My daughter wants me to make a garlic soap...doesn't sound to pleasant to me either

Well, if a clove of garlic can ward off evil spirits, stands to reason a good ,strong garlic soap would make the devil himself run like
Well, if a clove of garlic can ward off evil spirits, stands to reason a good ,strong garlic soap would make the devil himself run like

Oh, I don't know, maybe if you throw in some tomato , a little basil...
Sorry were we talking about soap?:shifty:
Just might get me thinking, maybe a garlic tomato soapie :D. Think it will scare away this HOT weather we are having. Sorry a little detour from the original post. It was your fault Obsidian you brought up soaping with cabbage :crazy:
If it chased away the hot weather we are having in Maine I would make a 100 lbs of it. I am sick of this heat. Give me 10 foot snow drifts and a snowmobile over this any day of the week!

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