Accurate pH testing of soap

[Kyle 3 Pass]

Hi all,

I just finished my second batch of soft shave soap and, both croaps tested between 8-10 for pH using test strips. I was wondering if there is a more accurate way of checking pH without doing the zap test? I was thinking about buying an electronic pH tester.

Generation 1 of my shave soap is a very good performer for me. Since I have very sensitive skin and a thick coarse beard, I decided to keep it unscented until I get the formula right. Nice slick, rich cushiony lather. Generation 2 will be tested tonight!

Ingredients: Water, stearic acid, coconut oil, castor oil, rice bran oil, potassium hydroxide, glycerine.


Thanks,

Kyle

 

[The Efficacious Gentleman]

Many pages have been devoted to this topic - I imagine many more will be!

The Zap test is in no way a pH test. It's a test for unsaopinfied lye - it cannot tell you what the pH of a soap is.

pH testing will tell you what the pH is, but does that always automatically mean that all of the lye is saponified? There was a discussion on what pH is skin safe or not, which had two different views on what was safe or even if pH alone was a usable measure of whether or not a soap is safe.

I also see a lot of bad press for the zap test, but I don't subscribe to it myself - regardless of pH, I view a soap as skin safe if I get no reaction.

 

[shunt2011]

I agree with Effy. I don't PH test as it's not really accurate for our soap. I do zap test just to make sure there is no active lye in my soaps. I make a shaving soap similar to yours and since it's hot process if you measure correctly your not a likely to have lye heavy soap one it's cooked properly. In general soap will have a PH of 8-10 and some may even be a bit higher.

 

[Kyle 3 Pass]

I just cooked the croaps as long as I thought necessary (45 minutes for 100 g sample). I may cook as long as an hour just to make sure.

No zap test ever for me. I agree Effy, if it doesn't react adversely to my skin, it is A-ok.

 

[The Efficacious Gentleman]

I............No zap test ever for me. I agree Effy, if it doesn't react adversely to my skin, it is A-ok.

I can understand why, but I have a 3-step process, mainly because my tongue is one of the most sensitive parts:

1 - rub a wet finger on the soap. Wait for a bit. If no reaction..........
2 - touch wet finger to tongue. If no reaction.................
3 - touch the soap to tongue. If no reaction, stick tongue out and make noises until something tasty has been drunk to remove the soapy taste

This way any "danger" to the tongue is very limited.

My way of looking at it, we have thermometers and even Infrared ones (I love mine!) but we still sip our tea or coffee to see if it's cool enough to drink, rather than using an IR thermometer!

 

[Saponista]

I considered using a pH meter, but it only works with liquid, so you would have to dissolve your soap in water. This would dilute it considerably and change the pH so in my opinion it's pretty pointless. Zap testing seems the best way to check your soap is definitely safe to use on your skin.

 

[Sinful7]

I'm a tongue tester too! Lol if its safe for my tongue its safe for most other parts of me!

 

[Susie]

I zap test. I now own a pH meter, but that is to make sure my liquid soaps are within a safe zone before dilution. I burned my tongue on some and thought about getting the meter.

 

[Gaspar Navarrete]

I also use the zap test regularly.

However, I do feel more comfortable knowing the pH of my soap, as well (7-10 for most soaps).

For testing pH, I found out that the juice of the red cabbage is a decent pH indicator. People use it to make pH test strips. See this link on how to use red cabbage:

http://chemistry.about.com/od/acidsbase1/a/red-cabbage-ph-indicator.htm

See this link for a picture of the color range of red cabbage:

http://images.flatworldknowledge.com/averillfwk/averillfwk-fig16_013.jpg

The cabbage juice changes to a wide variety of colors, making it easy for one to discern the pH. I never EVER want to get a yellow color.

 

[The Efficacious Gentleman]

..................I do feel more comfortable knowing the pH of my soap, as well (7-10 for most soaps).................

You've made a pH neutral soap?

 

[nframe]

What have you found that removes the soapy taste?

 

[The Efficacious Gentleman]

Red wine works a treat

 

[nframe]

Red wine works a treat

Great! Another excuse to have a glass of red wine!

 

[shunt2011]

Gaspar, how are you getting a ph of 7 (neutral)? CP/HP Soap is at least 8-10 and some are higher. Soap is cannot test neutral or it's not soap

 

[Gaspar Navarrete]

You've made a pH neutral soap?

Gaspar, how are you getting a ph of 7 (neutral)? CP/HP Soap is at least 8-10 and some are higher. Soap is cannot test neutral or it's not soap

There was a misunderstanding.

People on this forum have said that soap is supposed to be between 7 and 10.

So thru the cabbage test, I check to see if my soap is in this range.

My last two batches have a pH of 10.