pH challenge by Dr. Kevin Dunn

[AliensrReal]

I see now and understand the problem and terminology. It might be possible. I may try it for fun. Thank you!

It’s not possible to make a soap with a ph of 7 or below.

 

[TWF Mystic]

Can you explain that with chemistry? At a pH of 7, the fatty acids will still be ionized. Its not until the pH drops to around 5 for most alkyl chain carboxylic acids that they become protonated. Unless Im missing something here, it should be possible to have a soap at pH 7 or even 6. I just lathered up one of my soaps and took the pH of the sudsy water. pH = 7.0. You cant make a soap at pH 7, because you need the hydroxide which is highly basic. but you can absolutely have a functional soap at pH 7.

 

[AliensrReal]

Can you explain that with chemistry? At a pH of 7, the fatty acids will still be ionized. Its not until the pH drops to around 5 for most alkyl chain carboxylic acids that they become protonated. Unless Im missing something here, it should be possible to have a soap at pH 7 or even 6. I just lathered up one of my soaps and took the pH of the sudsy water. pH = 7.0. You cant make a soap at pH 7, because you need the hydroxide which is highly basic. but you can absolutely have a functional soap at pH 7.

That’s not a precise way of testing pH. The whole thread is about why a ph of 7 in soap can’t happen. You can make syndet bars ph of 7. @DeeAnna explained to you why. This whole thread is all about why you can’t get a pH 7 in soap.

 

[TWF Mystic]

That’s not a precise way of testing pH. The whole thread is about why a ph of 7 in soap can’t happen. You can make syndet bars ph of 7. @DeeAnna explained to you why. This whole thread is all about why you can’t get a pH 7 in soap.

But you can get a pH 7 in soap. Just not directly. You need to titrate it down a bit after the saponification. Thats why I said it would be easier to do with a liquid soap because it doesn't solidify. You would need to dissolve the bar soap to a liquid before you could adjust the pH down. I think perhaps this thread suffers from inexact wording or an unclear thesis.

 

[Bronxboyz]

Can you explain that with chemistry? At a pH of 7, the fatty acids will still be ionized. Its not until the pH drops to around 5 for most alkyl chain carboxylic acids that they become protonated. Unless Im missing something here, it should be possible to have a soap at pH 7 or even 6. I just lathered up one of my soaps and took the pH of the sudsy water. pH = 7.0. You cant make a soap at pH 7, because you need the hydroxide which is highly basic. but you can absolutely have a functional soap at pH 7.

Can I ask a question? What are your reasons for wanting to lower the pH of a cold process soap? A soap is going to fall somewhere between 9 and 11. It's supposed to be slightly alkaline, that's what makes it handmade cold process soap. It's good to have an understanding of the pH scale, and where soap and other substances fall on the scale. However, you never need to test the pH of a cold process soap or know what it is. Visually you will know if the soap is good or bad from the time it traces. Soap is mild from the second you take it out of insulation, and it's not less mild then a more cured soap. Only the water content is different, which directly affects lather , and the bar firms up. So why are soapmakers concerned about testing or changing the pH?

 

[TWF Mystic]

But you can get a pH 7 in soap. Just not directly. You need to titrate it down a bit after the saponification. Thats why I said it would be easier to do with a liquid soap because it doesn't solidify. You would need to dissolve the bar soap to a liquid before you could adjust the pH down. I think perhaps this thread suffers from inexact wording or an unclear thesis.

I hope that didnt sound rude. what I mean to say is, saponification will not give a neutral soap directly. It will be slightly basic, maybe pH 8 or so at complete saponification. Then you would adjust the pH down with a bit of acid until you came to pH 7. the soap would still work at pH 7 based in the chemistry. But as you go lower in pH eventually it would quit working as the alkyl salts become protonated, beginning ~pH 6 or lower.

Can I ask a question? What are your reasons for wanting to lower the pH of a cold process soap? A soap is going to fall somewhere between 9 and 11. It's supposed to be slightly alkaline, that's what makes it handmade cold process soap. It's good to have an understanding of the pH scale, and where soap and other substances fall on the scale. However, you never need to test the pH of a cold process soap or know what it is. Visually you will know if the soap is good or bad from the time it traces. Soap is mild from the second you take it out of insulation, and it's not less mild then a more cured soap. Only the water content is different, which directly affects lather , and the bar firms up. So why are soapmakers concerned about testing or changing the pH?

For me its a scientific argument. It was stated that a pH 7 soap would not work, or couldnt be made. I disagree. But I myself don’t want to make one, except to show that it can be done.

 

[paradisi]

For me its a scientific argument. It was stated that a pH 7 soap would not work, or couldnt be made. I disagree. But I myself don’t want to make one, except to show that it can be done.

It cannot be done. As this whole thread has documented with science. Perhaps you could find a more attainable goal.

 

[DeeAnna]

It's time to draw this discussion to a close.