# PH reduction



## Rhum (Jun 25, 2016)

Hello 

I've made simple liquid soap with coconut oil, koh and glycerine instead of water twice @5% @ 10% super fat using Soapee calculator and I'm happy with the results just PH. 
and of course diluted 1:1 by glycerine
The paper Ph meter stick shows PH of  around 9 and its too high besides my skin sometime after using it become dry and I think its because of high ph
In addition to that factory made LS had the ph of about 7

I'd be so grateful if  anybody suggest solution to lower the ph while remaining the soap  specs.

thank you  so much  in advance


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## shunt2011 (Jun 25, 2016)

Hello and welcome to the forum.

You cannot lower your ph to neutral. Handmade soap bar and liquid will have a PH between 8.5-12.  You may need to look at using surfactants.  Check out swiftcraftymonkey.com.  Also, using too high if a SF could cause separation.


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## Rhum (Jun 25, 2016)

shunt2011 said:


> Hello and welcome to the forum.
> 
> You cannot lower your ph to neutral. Handmade soap bar and liquid will have a PH between 8.5-12.  You may need to look at using surfactants.  Check out swiftcraftymonkey.com.  Also, using too high if a SF could cause separation.


thanks a billion for your info, I've been looking for such  a source badly
best wishes


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## Susie (Jun 25, 2016)

You should post your entire recipe in weights, and we can troubleshoot it for you.  It probably is not the pH bothering you, and those pH strips are notoriously inaccurate when trying to get the pH of soap.  Also, a soap made with only coconut oil is going to be drying.  There are other recipes out there.

You have, according to your post, a 5% superfat of one recipe, and a 10% superfat in the next, if I understand it correctly.  Oils/fats are acidic.  You can't lower your pH any further.  I am really surprised that you do not have a LOT of separation in those two recipes.


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## Rhum (Jun 26, 2016)

Susie said:


> You should post your entire recipe in weights, and we can troubleshoot it for you.  It probably is not the pH bothering you, and those pH strips are notoriously inaccurate when trying to get the pH of soap.  Also, a soap made with only coconut oil is going to be drying.  There are other recipes out there.
> 
> You have, according to your post, a 5% superfat of one recipe, and a 10% superfat in the next, if I understand it correctly.  Oils/fats are acidic.  You can't lower your pH any further.  I am really surprised that you do not have a LOT of separation in those two recipes.


hi Susie, i really appreciate your advice, here is the recipes:
#1  coconut 75degree 150 gr, koh @87.5 purity 42gr, glycerine 60gr as 38% of oil, superfat 5 %

#2 coconut 75degree 100gr, koh @85% purity 27gr, glycerine 64gr as 30% lye concentration 

would you mention some oils you intended above that do not cause skin dry
thanks  alot


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## Susie (Jun 26, 2016)

It is definitely your oils drying your skin.  Here is a recipe I blatantly stole from IrishLass (she shared it publicly), then tweaked it a tiny bit.  It makes luscious soap.  You can obtain all the oils from your local grocery store and pharmacy.  The castor oil will be in the laxative section.

Coconut Oil 25% 8 oz
Olive Oil 65% 20.8 oz
Castor Oil 10% 3.2 oz

KOH 7.1 oz (set calculator to 90% purity)
Water 10 oz
Sugar 1 tablespoon
Glycerin 11.3 oz

Melt and mix the oils. Add the glycerin to the oils.
Mix the KOH in small increments, stirring vigorously, with the water. (Save a tablespoon out to mix with the sugar, then dump that into the oils.) 
Once the KOH is completely dissolved, add it to the oils. 
Stickblend until you get an applesauce, you will then think it is ready, it is not. Continue to stickblend, it will go back to liquid, but once it is liquid, be prepared for either flying bubbles or almost instantaneous paste. I have had it do both on the various batches I have made. Either way, you are done stickblending. 

Cover the pot and walk away. I usually clean up all my soaping stuff and wash the dishes. Once you have taken a break for half an hour or more, start checking the paste. Once you see it looking like vaseline was mixed in, you can zap check it. If it is zapless, you can begin dilution. My theory is that the hotter your oils and your KOH/water mixture, the less time it takes to hit gel stage, but I have no proof. I have had this take as little as 20 minutes, and as long as 4 hours.

If you want to stickblend less, (IrishLass does not stickblend at all, just uses a whisk to get it to flying bubble stage.  I am an impatient sort, so I stickblend.) just stickblend until it no longer separates when you stop.  Then put a lid on it and walk away.  Then start checking it for the "vaseline" appearance in about an hour.


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## DeeAnna (Jun 26, 2016)

Susie's advice is the same as mine -- pure coconut oil soap is going to be VERY harsh to the skin as a liquid soap. It's fine for household cleaning or laundry, but not fine for skin. I use the same blend of fats as Susie's recipe and like it very well. I even use this soap when wet felting when I know my hands will be in soapy water for hours, and this soap does not dry my skin.

Another tip is to use a 25% lye concentration rather than 30% concentration. This means there are 3 parts of water and/or glycerin to 1 part KOH. That extra liquid will make the soap paste easier to stir and to dilute. To give you an example of what I mean, Susie's recipe uses 25% lye concentration -- 10 oz water, 11.3 oz glycerin -- for a total of 21.3 oz -- and 7.1 oz KOH.


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## Rhum (Jun 26, 2016)

Thank you so much dear Susie and DeeAnna, I'll take them into  practice and let you know the outcomes
I really appreciate your time and effort made to respond, hope could make up later
much gratitude


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## Seawolfe (Jun 26, 2016)

Yeah, coconut glycerine soap is what I use for my dishes (though at 0% SF). Susie gave you a much nicer recipe for skin. Another hint for when diluting from IrishLass: add 3% paste weight of sodium lactate - it helps the sticky paste dissolve easier. Also remember that on any new recipe your dilution will change, so you have to kind of sneak up on it.


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## IrishLass (Jun 26, 2016)

Susie said:


> Here is a recipe I blatantly stole from IrishLass (she shared it publicly),


 
LOL.....And in turn, I originally got it from 3bees~1flower (Carrie Peterson), who also happened to have shared it publically.  (I just wanted to give the original credit to whom it was due) 




			
				DeeAnna said:
			
		

> Another tip is to use a 25% lye concentration rather than 30% concentration. This means there are 3 parts of water and/or glycerin to 1 part KOH. That extra liquid will make the soap paste easier to stir and to dilute. To give you an example of what I mean, Susie's recipe uses 25% lye concentration -- 10 oz water, 11.3 oz glycerin -- for a total of 21.3 oz -- and 7.1 oz KOH.


 
Ditto what DeeAnna said on the 25% lye concentration.  Although I would never use that much water when making bar-type soap, I find it to be absolutely essential/necessary when making liquid soap.


IrishLass


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## topofmurrayhill (Jun 26, 2016)

Rhum said:


> #1  coconut 75degree 150 gr, koh @87.5 purity 42gr, glycerine 60gr as 38% of oil, superfat 5 %
> #2 coconut 75degree 100gr, koh @85% purity 27gr, glycerine 64gr as 30% lye concentration



To dissolve KOH, you need at least 2 1/2 parts glycerin, so the maximum KOH concentration would be 28%. If you didn't use any water, at least recipe #1 and maybe both of them could not have resulted in a clear KOH solution. But I may have misunderstood what you did.



DeeAnna said:


> Another tip is to use a 25% lye concentration rather than 30% concentration. This means there are 3 parts of water and/or glycerin to 1 part KOH. That extra liquid will make the soap paste easier to stir and to dilute. To give you an example of what I mean, Susie's recipe uses 25% lye concentration -- 10 oz water, 11.3 oz glycerin -- for a total of 21.3 oz -- and 7.1 oz KOH.





IrishLass said:


> Ditto what DeeAnna said on the 25% lye concentration. Although I would never use that much water when making bar-type soap, I find it to be absolutely essential/necessary when making liquid soap.



The lye concentration can be less than 25% (more liquid) when you are using a lot of glycerin.

Instructions based on the glycerin method call for 3 parts glycerin to 1 part KOH. Let's say for example 300 g water to 100 g KOH. Then you dissolve the KOH in the glycerin instead of water. Since dissolving the KOH directly in glycerin is dangerous due to the high heat required and the potential for boil-overs of a hot caustic liquid, you can replicate such a recipe like this:

-- Dissolve 100 g KOH in 100 g water.

-- Add that solution to 300 g room temp glycerin.

-- Subtract the 100 g water from the dilution water.

That is more liquid up front than normally called for (only 20% KOH) but it works because of the glycerin. It also replicates a glycerin method recipe exactly while being much easier, safer and faster.


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## Rhum (Jun 27, 2016)

hello and thank you all
have you ever measured the ph of this particular recipe meticulously?


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## The Efficacious Gentleman (Jun 27, 2016)

Why would someone do that? pH is not important for soap making. A soap can have a lower pH than another but not be as nice to use, because of other factors.


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## hlecter (Jun 27, 2016)

Very helpful posts!

I made several times the glycerin liquid soap the one that Susie described on post #6 with success. 
It works really good but i want to use it on my face and so its pH its too high for my skin as i measured it at 8.5...

Could i use some citric acid to neutralize it? Just a thought, i haven' t tried it before but i read other folks did...


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## shunt2011 (Jun 27, 2016)

hlecter said:


> Very helpful posts!
> 
> I made several times the glycerin liquid soap the one that Susie described on post #6 with success.
> It works really good but i want to use it on my face and so its pH its too high for my skin as i measured it at 8.5...
> ...


 
You cannot get the ph down to neutral.  It won't be soap. It will separate.  Soap will have a ph of 8.5-11 and maybe a bit higher.  That is what makes it soap.

I highly recommend checking out swiftcraftymoney.com.  You may need for non soap cleansers.

I use soap on my face with no issues.  Especially salt soap.  I prefer the bars to the liquid for my face though.  I


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## hlecter (Jun 27, 2016)

shunt2011 said:


> You cannot get the ph down to neutral.  It won't be soap. It will separate.  Soap will have a ph of 8.5-11 and maybe a bit higher.  That is what makes it soap.
> 
> I highly recommend checking out swiftcraftymoney.com.  You may need for non soap cleansers.
> 
> I use soap on my face with no issues.  Especially salt soap.  I prefer the bars to the liquid for my face though.  I



I ve read on swiftcraftymonkey and on other forum/blogs that soap bars arent good for hair and face because of their pH.. 

I ve tried them on my hair and on face of course and i havent any problem so far. But when i read all these things i stoped using them so often as before...


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## Susie (Jun 27, 2016)

Although I use commercial shampoo and conditioner on my hair, I use the same soap on my face as the rest of my body.  Every single day.  I have never had any problem with it.


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## shunt2011 (Jun 27, 2016)

Ditto. I don't use my soap on my hair but everything else is no issue.


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## IrishLass (Jun 27, 2016)

I don't use any of my lye-based soaps on my hair or my face. I've tried it, but the higher pH doesn't play nice with me in those areas. In regards to my face- even commercial-brand syndets don't play nice with me there either, so I use just plain water and a facial cloth to wash my face (which actually works great for me). For my hair, I use commercial-brand syndet shampoos/conditioners, which work really nice for me there. For the rest of me, I use my soap without any issues.


IrishLass


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## Rhum (Jun 27, 2016)

according to recent posts i should say i've been washing my hair with handmade olive soap bars that is sold here couple of months and recently with salt bar i made with coconut oil.
i'm still happy with it bcoze makes my hair more tender but one worry, scalp ph is said to be 5.5, should i watch for a sign of any adverse effect? 
btw is it male or female related?


The Efficacious Gentleman said:


> Why would someone do that? pH is not important for soap making. A soap can have a lower pH than another but not be as nice to use, because of other factors.


thank you for your notice but how could a soap have high ph and still doesn't wash all the skin oils and moisture? I'm asking to know more, any comprehensive online source you suggest about the factors you said?


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## kchaystack (Jun 27, 2016)

Rhum said:


> thank you for your notice but how could a soap have high ph and still doesn't wash all the skin oils and moisture? I'm asking to know more, any comprehensive online source you suggest about the factors you said?



The book Scientific Soapmaking by Dr. Kevin Dunn.  His website is http://cavemanchemistry.com/scisoap/

But you have not given us any sources for your info so we have no way to refute your claims.


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## Susie (Jun 27, 2016)

The oils you make the soap out of and the superfat you use has more to do with whether your skin gets stripped of oils or not.


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## Dahila (Jun 27, 2016)

hlecter said:


> I ve read on swiftcraftymonkey and on other forum/blogs that soap bars arent good for hair and face because of their pH..
> 
> I ve tried them on my hair and on face of course and i havent any problem so far. But when i read all these things i stoped using them so often as before...


For hair not but face is a different story.  Our body will do everything to keep it in balance and from 10-15 minutes skin ph goes back to the one it suppose to be ,  Healthy blood ph is 7.4 plus minus.  I wash my face with soap occasionally activated charcoal soap, and have no problems.  For hair I make a shampoo bar using very mild surfacants,  (Susan's blog)


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## The Efficacious Gentleman (Jun 28, 2016)

There is more than enough on this forum alone about pH and irritation not being linked - some of the mildest commercial soaps have pH levels higher than 10 and one even had 12. Some of those classed as most irritating were lower in pH. 

Low pH does not automatically equate to a milder soap. Higher pH also does not automatically equate to a milder soap. A pH does not in itself tell us if a soap is safe to use or not. Which is why I said that for what we do, pH is really taking you down a wrong path


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## Susie (Jun 28, 2016)

The Efficacious Gentleman said:


> There is more than enough on this forum alone about pH and irritation not being linked - some of the mildest commercial soaps have pH levels higher than 10 and one even had 12. Some of those classed as most irritating were lower in pH.
> 
> Low pH does not automatically equate to a milder soap. Higher pH also does not automatically equate to a milder soap. A pH does not in itself tell us if a soap is safe to use or not. Which is why I said that for what we do, pH is really taking you down a wrong path



^^^^This!

Soap, however, is not for everyone's hair.  Soap will damage some people's hair.  Skin is a different story.


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## DeeAnna (Jun 28, 2016)

Rhum said:


> ...how could a soap have high ph and still doesn't wash all the skin oils and moisture?...



I get the impression that you are thinking pH is only thing that affects the cleansing ability of a soap. The fatty acids used to make a soap are far more important to the properties of the soap than its pH, assuming the soap is properly made so it does not contain free alkalinity (excess lye). 

For example, a mostly oleic soap (olive oil) will have a higher pH than a mostly lauric-myristic soap (coconut oil). The coconut oil soap will be much harsher to the skin than the olive oil soap, however -- it will remove too much of the natural oils and proteins on the surface of the skin, leaving the skin feeling dry and perhaps irritated. One would expect the opposite result based on pH alone, so why is this the case? You have to look at the fatty acids in the soap, not the pH.

http://www.soapmakingforum.com/showthread.php?t=50018
http://www.soapmakingforum.com/showthread.php?p=510429
http://www.soapmakingforum.com/showthread.php?t=48845


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## hlecter (Jun 29, 2016)

The Efficacious Gentleman said:


> There is more than enough on this forum alone about pH and irritation not being linked - some of the mildest commercial soaps have pH levels higher than 10 and one even had 12. Some of those classed as most irritating were lower in pH.
> 
> Low pH does not automatically equate to a milder soap. Higher pH also does not automatically equate to a milder soap. A pH does not in itself tell us if a soap is safe to use or not. Which is why I said that for what we do, pH is really taking you down a wrong path



So could we say that the theory of some skin products and their pH has to be 5.5 is mostly a marketing? But for hair care products its somehow important...


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## The Efficacious Gentleman (Jun 29, 2016)

I would think that not grouping skin care and hair care together in general is a no brainer as skin is not hair and hair is not skin. How one cares for a cat is different to how one cares for a dog, even though both are four legged animals. 

As the topic is skin care, we'll stick to that. If the acid mantle is 5.5 and all that, then even water creates a disruption to it. People used non pH 5.5 products for ages and had great skin. It is marketing, as 10 minutes on this forum will tell you


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## DeeAnna (Jun 29, 2016)

Skin can balance and repair itself. Hair cannot. IMO that's the biggest difference in a nutshell. There is at least one research study that shows the skin pH is altered even by washing with water, but it recovers quickly. As long as someone doesn't wash obsessively, using soap on the skin is not an issue. 

The first image is a chart of the skin irritancy of commercial soap and non-soap cleansers vs. their pH. Athough there is a trend of irritancy going up as pH goes up, it's not a 100% correlation -- some of the least irritating cleansers have the highest pH (ex: Johnson's baby). The second image is the same information from the same source, but for the soap products only -- a little easier to digest if you only want to consider soaps by themselves.

I want to point out the pH of the commercial soaps ranges from 9.8 to 12.4. It annoys me when people assume, magically, that handcrafted soap is greatly different and somehow the pH should be greatly lower. It's lye-based soap ... it's going to have an alkaline pH.


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## Susie (Jun 29, 2016)

Let's also remember that the outer layer of the epidermis is made of 10-25 (or more) layers of dead skin cells that are constantly sloughing off.  They are there to protect the body from anything getting in.  You really have to scrub hard to get down even to 5 or so layers.  This means that all you are washing is dead cells anyway.  It is not going to be adversely affected by a pH within the range of normal hand made soap long term.  

What affects my skin the most is the superfat and the oils I use.  I have dry skin already, with very little oil production even in my T zone on my face.  I do not need any soap to strip more of those precious oils off of my skin.  That means lower coconut oil, and superfat 5-8% always.  Your skin may need different treatment.


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## topofmurrayhill (Jun 29, 2016)

I know that high-pH soap stings the eyes more than lower-pH syndet. That's the whole point of "no more tears" advertising and is one of the established advantages of syndets. Beyond that, I don't personally experience significant issues with soap. Someone else might.

Deeana posts data from a research study and states that the correlation between pH and irritation isn't 100%. It would be remarkable if it was. All we need is for the correlation to be significant. The SAME study that data comes from reaches the following conclusions:

_A significant correlation between pH and the [Irritation Index] of cleansers was found (P < 0.006). Most products recommended for sensitive skin have a considerable irritation effect, which is related to the pH of the product. Better regulation of advertisement specifications including the pH level and type of cleanser contained is necessary for the majority of soaps and cleansers._

P < 0.006 means that statistically it's extremely unlikely to be a coincidence.

I don't think we need to bend over backwards to say that syndets don't have a lower irritation potential because of their lower pH. They actually do, and rebuking someone for their interest in the pH of cleansers is not really appropriate in place of a reasoned response. It is ALSO true that concentrating a lot on the pH of artisanal soap isn't too useful. It is what it is, and there are limited things you can do about it.

I like making soap and I like using it. If that describes you too, then pH probably isn't a big issue for you. If you prefer how lower-pH products work for you, then syndets might be a better option. We have experienced soapmakers here who like them.


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## AustinStraight (Jun 30, 2016)

Can't the acid mantle be washed off by non-alkaline cleansers, too?  If it's basically just a layer of lipids + some other things, wouldn't you think any surfactant, CP soap or otherwise, would be able to remove it?


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## topofmurrayhill (Jun 30, 2016)

AustinStraight said:


> Can't the acid mantle be washed off by non-alkaline cleansers, too?  If it's basically just a layer of lipids + some other things, wouldn't you think any surfactant, CP soap or otherwise, would be able to remove it?



The "acid mantle" is a bit of a buzzword term. Reality turns out to be more complicated. Lipids do get washed away to one extent or another by any surfactant, but they don't have a pH. Acidity or alkalinity is a property of the water-based solution that permeates the skin.

The pH of a cleanser applied to the skin has a significant effect on that. There is a short-term effect (a few hours) that has been postulated to be the ONLY effect. However, there turns out to be a longer-term effect as well. Ultimately, there is a strong correlation between pH and the potential for irritation, due at least partially to the corrosive effect of high pH on proteins.

There seems to be a particular benefit for some people to using a slightly acidic cleanser, and it seems to be fine for people in general. Slightly acidic is better than neutral is better than alkaline. The most interesting paper I have on this comes from behind one of those nasty paywalls so I can't really share it.

These considerations usually come down to soap versus syndets. However, despite the fact that it gets dismissed out of hand here, you CAN make soap less alkaline and more mild. It's debatable how practical this is, but the principle is straightforward. The soap needs to be superfatted with fatty acids instead of oil. That means either making the soap with fatty acids instead of oil and using a lye discount, or you can fully saponify the oils and acidify the soap to separate some of the fatty acids.

I would guess that IrishLass' Cocoa/Shea LS superfatted with stearic acid is pretty gentle.


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## The Efficacious Gentleman (Jun 30, 2016)

topofmurrayhill said:


> ...... I don't think we need to bend over backwards to say that syndets don't have a lower irritation potential because of their lower pH. They actually do, and rebuking someone for their interest in the pH of cleansers is not really appropriate in place of a reasoned response. It is ALSO true that concentrating a lot on the pH of artisanal soap isn't too useful........




As the thread is about lowering the pH of a lye based soap because "low pH is best" I think that it is right to point out that pH is a false lead - the interest is not in cleansers as such, but lye-based soap. 

While the study found a correlation between cleanser irritation and pH, the lye based soaps show no such correlation. As the aim is to have low irritation and it was assumed that pH was the key, it's important to keep those two points clear that low pH does not mean it's better for the skin than a higher pH. Maybe with syndets, but not when we include real soaps.


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## ngian (Jun 30, 2016)

topofmurrayhill said:


> These considerations usually come down to soap versus syndets. However, despite the fact that it gets dismissed out of hand here, you CAN make soap less alkaline and more mild. It's debatable how practical this is, but the principle is straightforward. The soap needs to be superfatted with fatty acids instead of oil. That means either making the soap with fatty acids instead of oil and using a lye discount, or you can fully saponify the oils and acidify the soap to separate some of the fatty acids.



Is this because free fatty acids lowers the pH in an aqueous solution while mono-di- triglycerides doesn't affect the pH at all? 

Or this is about the fatty acid / soap equilibrium (pH and PKa values of each fatty acid)?


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## DeeAnna (Jun 30, 2016)

The Efficacious Gentleman said:


> As the thread is about lowering the pH of a lye based soap because "low pH is best" I think that it is right to point out that pH is a false lead - the interest is not in cleansers as such, but lye-based soap....



This is precisely the point I was trying to make. Thanks, Gent.


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## topofmurrayhill (Jun 30, 2016)

The Efficacious Gentleman said:


> As the thread is about lowering the pH of a lye based soap because "low pH is best" I think that it is right to point out that pH is a false lead - the interest is not in cleansers as such, but lye-based soap.



The relationship between solution pH and clinical irritancy 
for carboxylic acid-based personal washing products 
RICHARD  I.  MURAHATA  and MICHAEL  P.  ARONSON, 
Unilever  Research  U.S
1994

Synopsis 

The influence of formulation pH on the irritation potential of slurries formed from two commercial  products composed entirely or partially of aliphatic carboxylic acid-based surfactants (fatty acids and their salts) was determined in vivo by use of a flex wash. Increasing the pH of a synthetic detergent/fatty acid slurry from its neutral value to a pH of 10 reduced its mildness. The neutral pH of the predominantly non-soap-based cleanser, therefore, makes a significant contribution to its mildness. If it were formulated at pH 10, it would be significantly harsher to the skin than the current neutral formulation.

_The pH also had a significant effect on the irritation potential of soap-based cleansers. Decreasing the pH of soap slurries from their "normal" pH of approximately 10 to pH 7 reduced their irritation potential. The difference in alkalinity, as measured by pH,  is directly related to the lower irritation potential of both of these formulations. These results demonstrate that pH has an important role in determining the differences in irritation potential of these complex skin cleansing compositions through effects on ionizable constituents._


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## topofmurrayhill (Jun 30, 2016)

ngian said:


> Is this because free fatty acids lowers the pH in an aqueous solution while mono-di- triglycerides doesn't affect the pH at all?
> 
> Or this is about the fatty acid / soap equilibrium (pH and PKa values of each fatty acid)?



It's about pKa and other factors that affect the proportion of soap to fatty acid. In the case of soap, it's chemistry and it's pH are related. The effect on the skin may relate intrinsically to the pH to some extent and also (according to the paper I quoted for The Gent) the formation of soap-fatty acid complexes that are milder for the skin than soap.

So the question of the pH of a liquid soap is probably relevant when you are comparing let's say IL's basic recipe with her cocoa/shea/stearic recipe.


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## The Efficacious Gentleman (Jun 30, 2016)

I would be interested to see how the pH was changed in these cases - if we are comparing a 100% co soap at its standard pH against the same soap but with the pH altered, we would need to account for the changed 'recipe' of the soap. 

Again, in what we do we do not work in theory, but practice. Lowering the pH of a liquid soap to 7 or 5.5 is not something an average soaper can look to do, especially not if they don't want to look at syndet/hybrid recipes. 

Which means more consideration should be given to formulating a good recipe that works for someone and thinking about a recipe in those terms rather than measuring the pH of a soap and looking to reduce it to improve it


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## topofmurrayhill (Jun 30, 2016)

Nobody is telling anyone what to be interested in when it comes to soap making, but pH is not uninteresting or irrelevant. While pragmatically it might not come up for most people, I would dismiss a new person's curiosity about it more thoughtfully.

If you happen to have hydrochloric acid lying around, you can lower the pH and make a little table salt in the process. I think the researchers did it that way. You can can use other acids or you can superfat with fatty acids in cases other than cold process soap.


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## penelopejane (Jun 30, 2016)

^^^ post 37hiw can that be when Johnsons baby soap is the least irritating but the highest pH?


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## The Efficacious Gentleman (Jun 30, 2016)

That is one reason why I can't, from those numbers (which are only part of the paper, of course) reconcile pH to mildness. There are certainly leanings from the numbers, but they are just that - a clear correlation is it not


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## topofmurrayhill (Jun 30, 2016)

penelopejane said:


> ^^^ post 37hiw can that be when Johnsons baby soap is the least irritating but the highest pH?



Those are two different studies and they each reach a conclusion in their own way. Unfortunately the paper in post 37 is not accessible for free. It's pretty interesting.

As for the previous paper the correlation with pH is high but not perfect. I'm curious about the baby soap since you mention it, so I'll take a look and come back if there is anything in the ingredients that might be interesting.


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## ngian (Jun 30, 2016)

If you are talking about jonshons Baby oat then it might be for the oatmeal flour (if it has any of it). 

http://thealabublog.com/2010/05/6-reasons-why-people-use-oatmeal-in-soap/


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## Susie (Jun 30, 2016)

topofmurrayhill said:


> The relationship between solution pH and clinical irritancy
> for carboxylic acid-based personal washing products
> RICHARD  I.  MURAHATA  and MICHAEL  P.  ARONSON,
> Unilever  Research  U.S
> ...



This in no way says that it decreases the irritation.  It says it decreases the irritation *potential*.  There is theoretically an irritation potential in anything that is not pH 7.  That does not mean that soap is irritating at pH 9.5 or 10.

Also, we are not making theoretical soap for theoretical skin.  We are making real soap for real skin in our homes. (most of us, anyway)


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## topofmurrayhill (Jun 30, 2016)

Susie said:


> This in no way says that it decreases the irritation.  It says it decreases the irritation *potential*.  There is theoretically an irritation potential in anything that is not pH 7.  That does not mean that soap is irritating at pH 9.5 or 10.



"Increased irritation potential" means the same thing as "more irritating". It's always a potential because not everyone reacts the same way under all circumstances. In vivo testing is done on humans to gather data (for instance, the frequency and/or severity of skin irritation in response to certain substances), which is then analyzed to see what conclusions can be drawn. The particular source I quoted in this case is a review -- a type of paper that tries to gather and summarize results from multiple studies in a certain area.

So, we have certainly have not run out of references, but I don't want to put any more energy into it. I would have to extract quotes for most of these studies because they are behind paywalls. I think people can gather that the reality concerning the effect of various cleansers' pH -- including soap -- might not be as simple or inconsequential as it's made out to be. Scientific Soapmaking even has some material on it.

The easiest way to explore the relevance to soapmaking, besides attempting to neutralize soap to a degree, is to superfat hot process or liquid soap with FFA. IrishLass does this with one of her LS recipes, and it's done in various commercial products because the technique is well known in the industry.

I am not telling anyone to be interested in this or anything else, but folks who haven't done a few things along these lines are not really in a position to assess how effective or worthwhile it is. Everyone can explore or ignore anything they want. However, it seems like a small handful of people are so highly invested in certain dogmatic answers on some subjects that you aren't allowed to question them. I will of course question anything as I see fit to.


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## Susie (Jun 30, 2016)

To say that the "Increased irritation potential" is the same thing as "more irritating" is saying that you are going to get every side effect of every medication you take.  There is the potential, of course, but the reality is something entirely different for the majority of people.  Which your next statement, "It's always a potential because not everyone reacts the same way under all circumstances." confirms.

I also have to question any source that is a major manufacturer of commercial "syndet" bars.

You, of course, have the right to question anything you see fit.  Just as we have the right to question and challenge anything you say as long as we all remain polite and keep somewhat on topic.


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## galaxyMLP (Jul 1, 2016)

My question in this case would be if we are SFing the soap with FFAs to lower the pH, wouldn't the percent of actual soap in the product be lower than in a product with out it? That is to say is a soap with added FFAs more mild because it has a lower pH or because it has a lower % of soap itself than its non-SFed, non-pH adjusted counterpart. 

Are there any studies out there that compare a soap directly made with triglycerides as a SF vs a soap with FFA as SF? I'd love to read them and also test it. I would love to make a soap with a lye excess and then add citric acid to bring down the pH vs an HP soap that is simply SFed with straight oil at the end. I wonder if it would have any effect. In this case it would be beneficial to know the true sap values of my oils and true concentration of my lye.

Edit: did the math, going to try it with coconut oil. I'll post on it in a few hours and track the results over 8 weeks. I haven't been this excited to soap in a while.


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## topofmurrayhill (Jul 1, 2016)

galaxyMLP said:


> My question in this case would be if we are SFing the soap with FFAs to lower the pH, wouldn't the percent of actual soap in the product be lower than in a product with out it? That is to say is a soap with added FFAs more mild because it has a lower pH or because it has a lower % of soap itself than its non-SFed, non-pH adjusted counterpart.
> 
> Are there any studies out there that compare a soap directly made with triglycerides as a SF vs a soap with FFA as SF? I'd love to read them and also test it. I would love to make a soap with a lye excess and then add citric acid to bring down the pH vs an HP soap that is simply SFed with straight oil at the end. I wonder if it would have any effect. In this case it would be beneficial to know the true sap values of my oils and true concentration of my lye.
> 
> Edit: did the math, going to try it with coconut oil. I'll post on it in a few hours and track the results over 8 weeks. I haven't been this excited to soap in a while.



This from the same review.


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## ngian (Jul 1, 2016)

Well I did Kevin's Dunn beautiful experiment with a soapy solution and when vinegar and ammonia was used, they affected the power of NaOH / KOH soap just by altering the PH of the water.

So I will show you the experiments he has already showed but I also used Phenolphtaleine so as to have a better visual understanding when and how the PH is altered.

For those that don't know, when Phenolphtaleine is in water, it changes its color to pink/fuchsia over 8.2pH until 13pH. At less than 8.2pH and greater than 13pH it is colorless.

So here is my demonstration: 





(The recipe for my Liquid Glycerin Soap was 65% Olive oil, 25% PalmKernel and 10% Castor with 3% superfat).

So we understand that the liquid soap is for sure over 9pH.






Now we see that when vinegar (2.6pH) is added, the suds are almost vanished and the pH was dropped below 8. But the solution is still able to produce very few bubbles and I guess that the pH is a little over soap's pKa. (for more info see page 228-229 at Kevin Dunn's book). 

I think that pH alone could irritate our skin (the higher it gets the more it might irritates) and when KOH/NaOH soap is also present in the solution the more soap molecules are forming in higher pH and thus more cleaning power they will have irritating the skin more. I'm not saying that everyone's skin will be irritated but the word potentially fits perfectly here. 

By adding fatty acids in a solution I guess that the pH will drop as acetic acid also is doing the same. Kevin Dunn also writes at p.228



> Makers of commodity soap solve this problem by including
> detergents with low pKa values or by mixing soap with fatty
> acids before pressing the resulting mixture into bars. By this
> means, they can precisely balance the ratio of acid to soap to
> get the optimum cleansing properties at the lowest possible pH.



TAGs, DAGs and MAGs I guess that they don't have the same affect on PH as oils don't have or influence pH. Maybe that's why they are called fatty *acids* because they might act like ones...

So to end my demonstration I will add the picture with the addition of ammonia (11pH) in the solution (after vinegar was added) which helps bringing back the suds as more soap molecules are forming with the rising of the pH.






I'm not sure if the above are all correct, I just wanted to share my thoughts and Dunn's great demonstration that helps the soaping community.


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## IrishLass (Jul 1, 2016)

Wow! I haven't visited this thread in several days, but I'm now glued to the interesting turn it is taking....and not just because my creamy cocoa/shea GLS formula with the added FFA keeps popping up in the conversation.  

Oh, that I had a pH meter to test the pH of my above-mentioned soap, because for the first time since I've been making it, I'm actually curious about what it might be! lol 

Barring a pH meter, I do have some lab-grade Macherey-Nagel plastic pH strips on hand instead (both the 2.0 - 9.0 strips and the 7.0 - 14.0 strips). Perhaps I'll give it a go with those just for the halibut.

The funny thing is that the only reason I even chose to add the stearic acid to that soap in the first place during dilution was for no other reason than to prettify things by turning the soap opaque and creamy/pearly looking. Ha! The possibility that the pH might be lowered slightly because of its addition never even entered into my mind. lol But now that my curiosity has been piqued, I will test it out, and I of course will also test some of my undiluted paste to compare.

In any case, for what its worth, and even if I do say so myself- the soap _is_ rather lovely and mild-feeling to my skin, even in spite of having 35% coconut oil in it.... although it does have a total S/F of about 7%. But then again, my other GLS formula with 25% CO and a lower, total, built-in/up front S/F of 3% (without any added FFA's) feels just as mild to me.... but admittedly not as decadently/luxuriously oomphy-feeling as the other in comparison.

I shouldn't think its pH is edging too much near the neutral zone, though, because there's no separation and it's got plenty of bubbly/creamy lather.

I'll let y'all know what my strips tell me.


IrishLass


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## IrishLass (Jul 2, 2016)

Well, I tested my creamy cocoa/shea GLS- the finished soap and also the undiluted paste of the same. They were from a batch I made a few months ago.

I made a (separate) 1% solution out of each, and I used my plastic lab-grade strips made by Macherey-Nagel to test (letting each strip sit in their respective solution for 1 minute). 

The finished soap with the stearic FFA superfat tested out at 8.5 pH, and the undiluted paste (sans any FFA as of yet) tested out between 9.5 and 10 pH. 

Interesting!


IrishLass


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## Sapo (Jul 3, 2016)

I'm not a chemist, I apologize if this is a dumb question .

When/if you over-neutralize, are the floaty white thingies basically FFAs?


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## topofmurrayhill (Jul 3, 2016)

Sapo said:


> I'm not a chemist, I apologize if this is a dumb question .
> 
> When/if you over-neutralize, are the floaty white thingies basically FFAs?



Yes!


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## Sapo (Jul 3, 2016)

So basically:

*Citric acid* + *LS* = *potassium citrate* (chelator, beneficial for hard water) + *FFAs* (pH reduction, potential irritation reduction, beneficial)

Any ideas how to emulsify the floaties back into the soap? Heating and waiting? I don't see a downside to adding it, just goodies.


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## Susie (Jul 3, 2016)

You will need to use some sort of emulsifier.  I do not use them, but I think IrishLass' favorite is PS80.


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## IrishLass (Jul 3, 2016)

I've personally never used the 'lye excess/neutralization' method, and so I've never had to deal with an over-neutralized soap, but if I ever found myself in that situation, my natural/first inclination would be to add more lye solution to it bit by bit until things came back together again......

....although truth be told, I might just throw caution to the wind and try heating things back up until the FFAs melted, stir in some PS80, and then wait for it to cool down to see how things fared...... I use PS80 all the time to emulsify my superfat into my liquid soap post dilution (which works great for me), but since I've never tried using it with an over-neutralized soap, I have no idea if or how well it would work. 

If, however, I decided to take the PS80 route and it looked like the PS80 was definitely working, but things were not 100% yet, I'd keep repeating the heat/add/cool cycle until it did.......... but if it didn't look like the PS80 was working at all, I'd stop what I was doing and go with the lye solution route instead.

As for how much of either to add..... that's the tricky part, since I'd be most likely using the 'flying-by-the-seat-of-my-pants method (but making sure to take notes along the way, of course). lol Having said that, though, I'd definitely start with small doses.


IrishLass


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## topofmurrayhill (Jul 3, 2016)

Sapo said:


> So basically:
> 
> *Citric acid* + *LS* = *potassium citrate* (chelator, beneficial for hard water) + *FFAs* (pH reduction, potential irritation reduction, beneficial)
> 
> Any ideas how to emulsify the floaties back into the soap? Heating and waiting? I don't see a downside to adding it, just goodies.



That's right as far as it goes, but be careful about assuming no downside. Things are seldom that simple. I can't get too specific because my experience is limited and not consistent, but neutralizing with a stronger acid releases all different FFAs rather than whatever you might have chosen to add. I think this could affect the odor of the soap or maybe how it reacts to the addition of fragrances or something else.


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## galaxyMLP (Jul 3, 2016)

Also keep in mind that FFAs are more reactive than triglycerides and you may experience rancidity more quickly without preservatives. I'll also be testing that in the little experiment I did.


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