# PH level of soap



## danielle22033 (Aug 27, 2013)

I just recently bought ph strips for my first time.  I tested quite a few of my bars of soap and all are about a 10.5!! That's insane! I am superfatting at around 8%, so wouldn't that mean I am already using less lye?  So I decided to test out a store bought bar that I have from my couponing faze, it was lever 2000 and it's ph was about a 9.5.  So either the strips are wrong or most bars of soap are on the higher ph end? I have not had a problem using my soap and nor have I had any complaints from anyone.

How do I make a milder PH bar of soap?

Thanks


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## sistrum (Aug 27, 2013)

PH strips are not a good way to check the ph of your soaps.  There are plenty of posts here about that.  If your soap is fine for you and everybody else why are you even worried?


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## danielle22033 (Aug 27, 2013)

sistrum said:


> PH strips are not a good way to check the ph of your soaps.  There are plenty of posts here about that.  If your soap is fine for you and everybody else why are you even worried?



I am worried because this is my business,  and its one thing for it being a bit high for me but for my customers is a different story.


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## Robert (Aug 27, 2013)

Sistrum is right that there are better ways to test alkalinity than pH strips, but whatever apparatus you use there are better and worse methods.  What dilution are you measuring soap pH at?


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## dagmar88 (Aug 27, 2013)

danielle22033 said:


> I am worried because this is my business,  and its one thing for it being a bit high for me but for my customers is a different story.



PH is not something to worry about at all. As long as your soap isn't lye heavy, it's just fine.


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## Skatergirl46 (Aug 27, 2013)

Your tongue is very sensitive. If the soap doesn't zap then it's good.


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## pamielynn (Aug 27, 2013)

Handmade soap has a high ph. If you are worried about ph, you should look into making synthetic bars.

http://www.soapmakingforum.com/showthread.php?t=26665


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## judymoody (Aug 27, 2013)

pH of CP soap is typically between 9-11.  It's alkaline by nature.


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## danielle22033 (Aug 28, 2013)

Robert said:


> Sistrum is right that there are better ways to test alkalinity than pH strips, but whatever apparatus you use there are better and worse methods.  What dilution are you measuring soap pH at?



I called my supplier and they chemist said that I should be lathering up the bar of soap then placing the strip directly on the bar to an accurate reading.


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## danielle22033 (Aug 28, 2013)

dagmar88 said:


> PH is not something to worry about at all. As long as your soap isn't lye heavy, it's just fine.



The ph level lets you know if it is lye heavy.


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## dagmar88 (Aug 28, 2013)

danielle22033 said:


> The ph level lets you know if it is lye heavy.



That could be handy if it was accurate.
Just zap test and ditch the test strips (for soap).


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## neeners (Aug 28, 2013)

i'm having this issue too with my soap and pH strips.  this means i'm going to have to taste my soap, isn't it??  I was trying to avoid this......


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## Skatergirl46 (Aug 28, 2013)

danielle22033 said:


> The ph level lets you know if it is lye heavy.



The zap test will tell you that.


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## DeeAnna (Aug 28, 2013)

To zap test the "coward's way", just dampen a fingertip, swipe it on the soap, and touch the fingertip to your tongue. Just a tiny touch will do it. 

If it's zappy, you'll instantly feel a sharp, clear, almost-electrical shock, usually with a strong metallic or bitter aftertaste. You'll have an involuntary "ewwww, I really don't want to do that again!" reaction. Rinse your mouth with a swig of fresh water and you'll be fine.

If it's not zappy, it might taste somewhat bitter, salty, or metallic; it might have an odd flavor from the fragrance you've added; or it might simply have a bland nothing-special taste. But your reaction to a non-zappy soap will be, at its worst, more of a "meh, I would rather not" kind of thing.

FWIW, I'm a coward when it comes to zap testing, but I have been known to swipe my tongue over some of my nicer tasting bars once I know they're fine.


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## neeners (Aug 28, 2013)

ok...I guess I can be brave tonight.....  will imagine I have war paint on my face while I stick my tongue on my bar of soap.  haha!


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## innerdiva73 (Aug 28, 2013)

The lower PH soaps are over 60% Olive oil.


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## CaraCara (Aug 28, 2013)

The PH will always be higher so don't worry about that. Do the zap test after a day or so. You will know if it zaps or not. If you've ever stuck your tongue on a 9 volt battery, it's a similar experience.


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## CaraCara (Aug 28, 2013)

innerdiva73 said:


> The lower PH soaps are over 60% Olive oil.


 
That's interesting. I always wondered if certain oils influenced the PH.  I will have to commit some time to research more.


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## Robert (Aug 28, 2013)

danielle22033 said:


> I called my supplier and they chemist said that I should be lathering up the bar of soap then placing the strip directly on the bar to an accurate reading.


You won't get a meaningful comparison between products unless you make a measured concentration by weight in water, the same each time.  Soap isn't a buffer; the pH of a solution of it is going be concentration-dependent.


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## danielle22033 (Aug 28, 2013)

innerdiva73 said:


> The lower PH soaps are over 60% Olive oil.



I tested my 100% olive oil soap and that too was a 10 with a 8% superfat


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## danielle22033 (Aug 28, 2013)

Robert said:


> You won't get a meaningful comparison between products unless you make a measured concentration by weight in water, the same each time.  Soap isn't a buffer; the pH of a solution of it is going be concentration-dependent.



I am not exactly sure what you mean by this?


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## dagmar88 (Aug 28, 2013)

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


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## innerdiva73 (Aug 28, 2013)

danielle22033 said:


> I tested my 100% olive oil soap and that too was a 10 with a 8% superfat



The PH in my Olive Oils soaps are always between 7-9.  I guess it has a lot with other factors.


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## dagmar88 (Aug 28, 2013)

innerdiva73 said:


> The PH in my Olive Oils soaps are always between 7-9. * I guess it has a lot with other factors.*




The way you measure. Soap is alkaline by nature. Soap with a pH of 7 is impossible.


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## innerdiva73 (Aug 29, 2013)

To the original poster, this info may help if your trying to understand PH and safe levels.
http://www.soap-made-easy.com/soap-ph.html

Just tested one of my 100% OO soap and got a reading of 8.  PH strips are not 100% accurate but they can give someone learning the trade a guideline to ensure their soaps are safe for use.


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## DeeAnna (Aug 29, 2013)

"...I always wondered if certain oils influenced the PH...."

Yes, they do. Or actually the mixture of fatty acids in the fats are what will determine the pH. Kevin Dunn in Scientific Soapmaking touches on this. Some excerpts from his book:

"...But even a good, mild, completely saponified soap is generally more or less alkaline, with a pH between 8 and 10. There is a temptation to attach too much importance to the pH registered by the test paper.... [O]ur only consideration is that the soap is not excessively alkaline. We'll refer to such a soap as tongue neutral..." (pp 77 in Section 4.4 The Tongue Test)

"...[T]he pH of a soap solution may vary over a considerable range. Consequently, pH alone will not tell us whether soap contains excess alkali.... [The total alkalinity test is a method of] precisely measuring the amount of excess alkali in soap...." (pp 245-246)

DeeAnna speaking: I'm going to waive my hands over the background behind the numbers listed below and simply say that this is the typical pH range for a soap made out of a single pure fatty acid. These values are taken from page 229 of Dunn's book. Since our soaps are made from mixed fatty acids, you won't see exactly these values. 

Lauric acid - Sodium laurate       7.5 - 10.1
Myristic acid - Sodium myristate       8.2 - 10.4
Palmitic acid - Sodium palmitate       8.8 - 10.7
Stearic acid - Sodium stearate       10.2 - 11.4
Oleic acid - Sodium oleate       9.9 - 11.2
Linoleic acid - Sodium linoleate       9.2 - 10.9
Linolenic acid - Sodium linolenate       8.3 - 10.4

DeeAnna again: The point to take away from these numbers is that the absolute lowest possible pH you could ever see is 7.5 and that would be if you made a soap from pure sodium laurate (found in coconut oil). A realistic pH range using mixed fatty acids would be 8 to 10 as Dunn says above. 

But pH is not the as precise as it should be to determine whether a soap might be a touch lye heavy or a safe "tongue neutral". A "normal" pH for, say a castile with lots of sodium oleate might be "too high" for a coconut oil soap with lots of sodium laurate and sodium myristate. That is the reason why pH is only a rough indicator -- the "total alkalinity" test is really the proof of the pudding if you want an absolute answer. The zap test is the low tech version of the TA test.

Just to be clear, these pH numbers are for 1% solutions of pure soap dissolved in water and the pH was measured with a properly calibrated lab-grade pH meter. The results from pH test strips rubbed over a damp soap bar won't give you this kind of accuracy.


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## new12soap (Aug 29, 2013)

innerdiva73 said:


> PH strips are not 100% accurate but they can give someone learning the trade a guideline to ensure their soaps are safe for use.


 
That is exactly the problem, no they don't. You can easily get an artificially low reading from test strips, they DO NOT accurately tell you the pH of your soap. Beginners learning the trade need to learn how to tell their soaps are safe, absolutely, and the bottom line is that pH strips are NOT going to tell them that.

Please read the link to miller soap about test strips that dagmar posted above.

If you are determined to measure the pH of soap, you are going to have to dissolve some soap in water and use a high quality and accurately calibrated pH meter, but again that will not tell you what you need to know. It is possible for a soap w a pH of 9 to be more harsh than one with a pH of 10, so again, pH really does not help.


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## Robert (Aug 29, 2013)

danielle22033 said:


> I am not exactly sure what you mean by this?


There are certain mixtures that are pH buffers.  You dilute them and the pH of the solution hardly changes.  (If they behaved perfectly according to model, the pH wouldn't change at all.  In reality, especially at the high end of concentrations, there are changes.)

Soap is not one of those mixtures.  There is no such thing as the pH of a soap.  There is only the pH of a given concentration of a soap, a certain weight of the soap in a certain volume or weight of water.  As you dilute the soap, the pH of the solution goes down.  If you just make lather, you don't know how much soap is dissolved in how much water.  You shouldn't vary the temperature either.

The pH strip has a series of pads on it, each of which has a substance or mixture of substances such that a reaction with it will go in one direction or another depending on whether the pH is above or below a certain point.  pH strips are particularly tricky when checking alkaline solutions, because carbon dioxide in the air will neutralize more alkali the longer you have the strip out in the air after dipping it.

pH is not the only measure of alkalinity of a soap.  When you do the tongue test, you're not just reacting to pH, but to excess strong alkali if they're present.  Since what you're probably interested primarily in is how the soap acts on someone's body, it's appropriate to use a sensitive part of the body like that to tell.


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## innerdiva73 (Aug 29, 2013)

new12soap said:


> That is exactly the problem, no they don't. You can easily get an artificially low reading from test strips, they DO NOT accurately tell you the pH of your soap. Beginners learning the trade need to learn how to tell their soaps are safe, absolutely, and the bottom line is that pH strips are NOT going to tell them that.
> 
> Please read the link to miller soap about test strips that dagmar posted above.
> 
> If you are determined to measure the pH of soap, you are going to have to dissolve some soap in water and use a high quality and accurately calibrated pH meter, but again that will not tell you what you need to know. It is possible for a soap w a pH of 9 to be more harsh than one with a pH of 10, so again, pH really does not help.



Guidelines are what people follow and if someone is trying to get an understanding then Guidelines are what they need. Here is the same article on Miller soap,

 "Conclusions:

Not all pH strips are created equal when it comes to testing soap. Some are inaccurate by as much as 2-3 units because the surfactant nature of soap can interfere with the indicator dyes used to make the strips. Others can give accurate readings that approximate those of a pH meter. Based on the pH strips I've tested, *laboratory grade plastic test strips are more accurate than paper test strips for testing soap.*



Recommendations for using test strips:

Some test strips need longer contact with the solution/slurry for an accurate reading. For best results, keep your test strip in the solution/slurry until the color no longer changes, perhaps 30 seconds or one minute.

Store your strips away from direct light which over time, can fade the dye indicators and interfere with accuracy.


Some people like myself are not comfortable using their tongue to zap test soap.


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## dagmar88 (Aug 29, 2013)

innerdiva73 said:


> Some people like myself are not comfortable using their tongue to zap test soap.



As explained above; even when the pH is accurately measured, that doesn't tell you if there's any excess lye.


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## shunt2011 (Aug 29, 2013)

So does making a little lather and touching it to the tip of your tongue.  As previously stated the ph strips are not accurate for testing our soap.


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## sistrum (Aug 29, 2013)

The tongue test has been used over a hundred years, even in factories.  It's a soap making tradition and the way it's done.


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## dagmar88 (Aug 30, 2013)

sistrum said:


> The tongue test has been used over a hundred years, even in factories.  It's a soap making tradition and the way it's done.




 I don't get the big deal. If you do everything right, it's not likely you'll get zapped anyway.
I brush my teeth with my soap when I've forgotten to buy toothpaste again.
After a good long cure, it's kind of sweet and not too yucky 8)


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## JaimeM (Aug 30, 2013)

dagmar88 said:


> I brush my teeth with my soap when I've forgotten to buy toothpaste again.
> After a good long cure, it's kind of sweet and not too yucky 8)



You are a rockstar and my new hero!!


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## dagmar88 (Aug 30, 2013)




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## verotxu (Aug 30, 2013)

Hello!

The pH of soap is alkaline because it is made from a strong alkali and a weak acid. In order to get soap with lower pH you should use weaker alkali.

Cheers


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## dagmar88 (Aug 30, 2013)

verotxu said:


> Hello!
> 
> The pH of soap is alkaline because it is made from a strong alkali and a weak acid. In order to get soap with lower pH you should use weaker alkali.
> 
> Cheers




Could you explain this statement?


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## DeeAnna (Aug 30, 2013)

"...to get soap with lower pH you should use weaker alkali...."

Sooooo ... you're suggesting the use of KOH or NH4OH, perhaps? I'm as curious as Dagmar is -- please explain!


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## verotxu (Aug 30, 2013)

The fatty acids are weak acids and NaOH is a strong alkali. Lets say that the NaOH "wins" over the fatty acids, and there are more OH in the final solution than protons, that is why the pH of the product is so alkaline. KOH is also strong, trietanolamina is weaker though but I have not tried myself


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## dagmar88 (Aug 30, 2013)

verotxu said:


> The fatty acids are weak acids and NaOH is a strong alkali. Lets say that the NaOH "wins" over the fatty acids, and there are more OH in the final solution than protons, that is why the pH of the product is so alkaline. KOH is also strong, trietanolamina is weaker though but I have not tried myself




You need hydroxide to make soap. :wink: No lye, no soap.
Saponification explained in a simple way:

http://www.soap-making-resource.com/how-is-soap-made.html


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## DeeAnna (Aug 30, 2013)

"...The fatty acids are weak acids and NaOH is a strong alkali. Lets say that the NaOH "wins" over the fatty acids, and there are more OH in the final solution than protons, that is why the pH of the product is so alkaline. KOH is also strong, trietanolamina is weaker though but I have not tried myself..."

First sentence -- Yes, that's very true.

Second sentence -- Yes, the pH is alkaline. I'm not quite sure what "the NaOH 'wins'" means, however. In a properly made soap, there should be a stoichometric excess of neutral fats or fatty acids.

Third sentence -- Triethanolamine? Sure, you can use it to make soap. I'd love to hear more about your experiences with the soap when you make and use it. In the meantime, I really would like to connect with handcrafted soap makers who are making this type of soap and more data on how it performs. Would you provide that information, please? Thanks!


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## Robert (Aug 30, 2013)

verotxu said:


> The pH of soap is alkaline because it is made from a strong alkali and a weak acid. In order to get soap with lower pH you should use weaker alkali.


You can do that, but it'll get you only so far.  Neutrogena soap is made with triethanolamine (TEA) rather than lye.  The solutions Neutrogena forms are less alkaline, with a lower pH, than are the corresponding solutions of sodium or potassium soaps.  But despite its name, it's still not quite neutral.  You can't get the pH of a soap solution too low before fatty acids come out of solution as fatty acids.  If you understand what this means technically, Neutrogena is a buffer mixture with a pH around 8 IIRC, between the pKa of triethanolammonium ion and that of the fatty acids in the soap.

If you'd like to try making a similar soap, you can use TEA or ammonia.  The trouble with using ammonia is that the product will still be alkaline enough to release ammonia gas and be stinky.  Some mechanic's soaps are made with ammonia as part of their alkali, and I'm told they stink on purpose to "show how strong the soap is".  TEA is less volatile, hence less stinky, although before neutralization it will like most amines smell like rotten fish; making soap with TEA in an unventilated facility would be unpleasant, I'm sure!


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## DeeAnna (Aug 30, 2013)

"...You can do that, but it'll get you only so far...."

Yep. I agree, Robert. Thanks for the explanation from your point of view. I am also hoping to learn the poster's reasoning behind his/her suggestion to use TEA -- perhaps s/he has a perspective to offer that you and I are missing?


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## Robert (Aug 30, 2013)

DeeAnna said:


> "...You can do that, but it'll get you only so far...."
> 
> Yep. I agree, Robert. Thanks for the explanation from your point of view. I am also hoping to learn the poster's reasoning behind his/her suggestion to use TEA -- perhaps s/he has a perspective to offer that you and I are missing?


I'm sure hir perspective is the same as that of the makers of Neutrogena.  I don't know of any home soapmakers using TEA, but it would be interesting to know of.  It may even be possible to saponify with TEA by an anhydrous process.

Theoretically it is possible to make soaps that give lower pH solutions by using extra fatty acid, just using the fatty acid-soap system itself as a single buffer.  I don't know whether that happens normally with superfatting.  The other Bob the soap expert said he thought that even in cold process, the extra fat is hydrolyzed into fatty acid & glycerol rather than being present as glyceride in the final product.  In a soap with excess f.a. theoretically the buffer formula would apply:

pH = pK - log([f.a.]/[soap])

But I have my doubts that it would come out that close to the model, given the very non-ideal solution characteristics of soap.  With TEA soap, though, I'm sure there would be effective buffering.


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## Jakeedin (Aug 31, 2013)

danielle22033. Up and until recently, I was really alarmed with myself when it came to pH levels. When I first used litmus strips, I found it difficult as it often gave me the impression 8.0 to something safe. Then I remembered that I was slightly colour blind so, I got myself a pH meter.
It was only until I have tested the soaps on myself and with my friends that I have come to accept that in CP soaps pH is usually in the bracket of 9.5 to 11.0, 10.5 and 10.0 is very normal even after curing. The important factor to me now, is the ingredients and how it would benefit the skin that matters to me most.


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## verotxu (Sep 1, 2013)

Hello!

I have been away for the weekend and unable to connect to the forum. 

As i have earlier posted I have not used myself TEA for making soap, I just got the info from a book about scientific book about cosmetics. I did not mean that you were able to get a soap with the same pH value of the one of the skin. I just said that you could lower the pH using a weaker alkali. 

Going back to the scientific debate. Soap is a salt made from a weak acid and a strong base. The soap will dissociate into a cation and an anion when it will be in contact with water. The cation (Na) comes from the strong base and consequently it will not have the strengh to react with anything. On the contrary the anion comes from a weak base and it has the strenght to react with water and produces OH which increases the pH of the solution. 

If the acid is stronger than the alkali, then the resulting pH of the soap will be acid; if the strenght of the acid and the base is equal the resulting pH will be neutral.

Cheers

Veronica


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## lhaase0217 (Sep 5, 2013)

*PH Levels in Soap*

After reading a thread and some odd posts, I am gathering that using PH test strips, or to test the PH levels, are basically a waste of time when a zap test is sufficient.

That being said, I still like to put the PH level on my labels for label appeal. I have used the test strips and found I received levels from 7.5 to about 9.5. This is satisfactory for me. I do want to invest in a PH meter sometime in the future.

I have found that using milks in your soap helps to lower the PH level, at least it did in my cupcake recipe. I made 3 batches, 2 with 1/2 water mixed with lye and 1/2 cold GM added to oils before lye/water solution; and the last with only water with the lye.

When I tested the batches, the 2 with GM were about 1.5 to 2.0 lower in PH value than the ones made with no GM.


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