# How to lower ph of a handmade CP soap?



## Soapmaker_CRO (Aug 18, 2010)

I need help on how to lower the pH of soap.

I have made a couple of natural soaps with lye and evan after 6 weeks PH is still around 10. 
I thought about using an acid to neutralize the base (NaOH), but I have not found an acid that is safe to use with NaOH that is also not deleterious to the skin. Also, I would like to know in which phase to add the acid or some other ingredient. 

Please, help


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## mariflo (Aug 18, 2010)

I think these threads will shed some light 

http://www.soapmakingforum.com/forum/vi ... hp?t=18978
http://www.soapmakingforum.com/forum/vi ... hp?t=17897

10 is within the normal PH range of lye soap. If it doesn't zap, you're fine. If you want a lower PH, look into syndets. If I remember correctly somebody on this forum posted a picture of her syndet shampoo bar. Use the search function and you'll find tons of info.


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## scouter139 (Aug 18, 2010)

I've thought about it a while back, trying to lower the ph...what about lemon or lime juice, both are acids and may offset the higher ph.  Don't know what would happen if you froze lemon or lime juice as your liquid and then added the lye.  Haven't gotten that far in my experimenting.  I also know that rain water has a lower ph than tap water.  Don't know if that would make a difference. What about adding lye to 1/2 the amount of water and then adding lemon or lime juice sometime during the soaping process.  

Good experiment to try.


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## evergreen (Aug 18, 2010)

scouter139 said:
			
		

> I've thought about it a while back, trying to lower the ph...what about lemon or lime juice, both are acids and may offset the higher ph.



1) Working off of this suggestion...what about rebatching the soap with very little water (grate it, add a few ounces of water, melt in a crock pot on warm for 6 hrs or so) and then add citric acid crystals?  You could top that off with some lemon essential oil to scent it.

2) If you had active lye still in the soap, you could just rebatch and add a small amount of olive oil. Cook the soap for a few minutes (as an HP soap) on a warm setting in the crock.  Check the pH and then pour into the mold. 

3) Another choice is to divide the soap in half...make a fresh batch of soap batter with a castile or bastile soap recipe and add the finely grated soap to that.  If it worked to your liking, you could do the same with the second half of the first soap if it hasn't changed to a lower ph by then.


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## soapsmurf (Aug 18, 2010)

If you get anywhere close to pH 8, true soap typically turns to sludge.


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## Beckis19 (Aug 18, 2010)

evergreen said:
			
		

> 1) Working off of this suggestion...what about rebatching the soap with very little water (grate it, add a few ounces of water, melt in a crock pot on warm for 6 hrs or so) and then add citric acid crystals?  You could top that off with some lemon essential oil to scent it.



Lol.  I was thinkig the same thing last weekend.  I had some soap scraps and rebatched them (boil-in-bag method),   and disolved  some Citric acid in milk I added to the batch.  As a previous poster mentioned, I ended up with sludge.


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## carebear (Aug 18, 2010)

evergreen said:
			
		

> 1) Working off of this suggestion...what about rebatching the soap with very little water (grate it, add a few ounces of water, melt in a crock pot on warm for 6 hrs or so) and then add citric acid crystals?  You could top that off with some lemon essential oil to scent it.


significantly reducing the pH of your soap results in NOT soap.  aka sludge.



			
				evergreen said:
			
		

> 2) If you had active lye still in the soap, you could just rebatch and add a small amount of olive oil. Cook the soap for a few minutes (as an HP soap) on a warm setting in the crock.  Check the pH and then pour into the mold.


adding oil will dilute a bit, but not impact the pH



			
				evergreen said:
			
		

> 3) Another choice is to divide the soap in half...make a fresh batch of soap batter with a castile or bastile soap recipe and add the finely grated soap to that.  If it worked to your liking, you could do the same with the second half of the first soap if it hasn't changed to a lower ph by then.


you lost me here - What would this accomplish?


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## evergreen (Aug 18, 2010)

>adding oil will dilute a bit, but not impact the pH

I said she could do this IF there was still lye in the soap...she could cook it a few minutes with the addition of a small amount of oil (hot process).  IT will reduce the pH IF there's still active lye in a soap.  I check the pH of my HP soap during the cooking process and I've seen it go down from 12 to 8 and then done a zap test to be sure.


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## soapsmurf (Aug 18, 2010)

Do you use a pH meter?  pH test strips will not give an accurate read with soap.


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## carebear (Aug 18, 2010)

evergreen said:
			
		

> >adding oil will dilute a bit, but not impact the pH
> 
> I said she could do this IF there was still lye in the soap...she could cook it a few minutes with the addition of a small amount of oil (hot process).  IT will reduce the pH IF there's still active lye in a soap.  I check the pH of my HP soap during the cooking process and I've seen it go down from 12 to 8 and then done a zap test to be sure.



ah yes, you are absolutely correct - IF there is excess lye then adding oil will help.  

For HP (with the right amount of lye) during the cooking process of course the pH goes down as the lye is consumed by the reaction.  Same holds true for CP soap during the spaonification phase.  It is the conversion of the oils and lye to the soap that does it  But during a rebatch of a soap which is not lye heavy it won't do anything.


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## epowers777 (Aug 18, 2010)

My book states that borax will lower the ph. Someone in this forum said it barely lowers the ph so it might help.


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## fasanis100 (Aug 18, 2010)

Citric acid lowers the PH of soap, but as was mentioned before a neutral PH on soap is not soap anymore.
There is no benefit in the skin to use a soap with a low PH.  There was a time that I had the same idea of using a neutral PH handmade soap, specially I was thinking about babies.  I researched a lot and even talked with some people.  The answer was usually the same.  Our skin has a neutral PH but when we use soap, the PH goes slightly higher and then goes back to neutral.  So unless your soap bar is very high (like 12 which you will feel right away) there is no benefit in using a neutral PH on soaps.


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## carebear (Aug 18, 2010)

epowers777 said:
			
		

> My book states that borax will lower the ph. Someone in this forum said it barely lowers the ph so it might help.



I know borax is used in liquid soapmaking but never understood it's benefit.  The pH of borax is about 9.5 (if memory serves, it's used to RAISE the pH in swimming pools) so it won't lower the pH of a properly made soap much.  

It's a pretty good buffer, as well, so can stabilize the pH, but that shouldn't be an issue if you've made your soap properly. 

http://chemistry.about.com/od/howthings ... xworks.htm

(and I believe the pH of skin is naturally somewhat acidic, and although washing with soap temporarily increases the pH it rapidly returns to normal all by itself)


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## IrishLass (Aug 19, 2010)

Soapmaker_CRO said:
			
		

> I need help on how to lower the pH of soap.
> 
> I have made a couple of natural soaps with lye and evan after 6 weeks PH is still around 10.
> 
> Please, help



If your soap's pH is 10, rejoice! You made it properly.   The pH of properly made and cured lye soap resides naturally on the alkaline side of the pH scale. It's just the nature of the beast. 

IrishLass


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## Beckis19 (Aug 19, 2010)

fasanis100 said:
			
		

> Citric acid lowers the PH of soap, but as was mentioned before a neutral PH on soap is not soap anymore.
> There is no benefit in the skin to use a soap with a low PH.  There was a time that I had the same idea of using a neutral PH handmade soap, specially I was thinking about babies.  I researched a lot and even talked with some people.  The answer was usually the same.  Our skin has a neutral PH but when we use soap, the PH goes slightly higher and then goes back to neutral.  So unless your soap bar is very high (like 12 which you will feel right away) there is no benefit in using a neutral PH on soaps.



Well, yes, but I was looking around the forums about shampoo barss and people's experiences with them, and found out that hair likes more of a neutral PH.  I was trying to make a shampoo bar that didn't frizz my hair.  Looks like there's no shortcut, I'll just have to keep on testing....      Too bad it wasn't until AFTER I added the citric acid that I got on to see what went wrong when I found I had sludge...


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## soapsmurf (Aug 19, 2010)

Beckis19 said:
			
		

> fasanis100 said:
> 
> 
> 
> ...


For best results with a 'poo bar, you really should look into syndets instead.


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## ChrisShepp (Aug 19, 2010)

soapsmurf said:
			
		

> For best results with a 'poo bar, you really should look into syndets instead.



Preface:  I am enjoying a giant umbrella drink, and my inhibitions are lowered as I type this...  :wink:   

EXACTLY. Thank you for the wise intervention, SoapSmurf.

There are certain unalienable truths, among them:

1. Soap is Soap. It is not Shampoo - regardless of what you label it or what part of the body you apply it to (i.e., hair)

2. Soap leaves a filmy residue. Every recipe. Yes, yours. Do you want that on your hair? People say, "Oh, I just mix up a PITA vinegar rinse." Seriously? Gimme a break!

3. Soap has a pH of 8 -10. That is THE end of the story.

4. If you require a lower pH, you are in search of something other than a 'shampoo bar' that is made of soap.

<ChrisShepp now steps off his virtual soapbox and apologizes to anybody whose feelings may have ben hurt by his somewhat tipsy rant... :wink:   >


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## MagiaDellaLuna (Aug 19, 2010)

ChrisShepp said:
			
		

> <ChrisShepp now steps off his virtual soapbox and apologizes to anybody whose feelings may have ben hurt by his somewhat tipsy rant... :wink:   >


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## Beckis19 (Aug 20, 2010)

ChrisShepp said:
			
		

> soapsmurf said:
> 
> 
> 
> ...


    I was just sharing my spur-of-the moment urge to try experimenting, and I didn't think to stop to check the forum to see what would happen.  Actually, I had told my hubby about the idea, he has a chemical engineering degree (though he is now an environmental engineer) and I guess he didn't give it too much thought since he didn't say anything about it not working.  So I know next time I want to experiment to consult those who have actually tried/know  :wink: 

No offence taken, but a little background, to help explain my madness: 

I wasn't aiming to have the poo bar be my every-day shampoo.  Though it would be nice if I could find one that worked, like some people have.  I'm a backpacker, and wanted to see about making a bar soap I could use for my hair as well (though I have to admit, Dr. Bronners is an interesting read at times, lol...) that I can take with me.  I don't want to wash my hair and leave syndets all around the Great Outdoors.  I was aiming for something that I could tolerate using to clean my hair when it starts to get really nasty.  I didn't know I was voilating the 4 Great Laws of Soap  :wink:


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## carebear (Aug 20, 2010)

ah, well then you should know that saponins will kill fish and all that good stuff, so even if you wash with real soap instead of synthetic detergent products you need to discard your soapy water away from lakes and streams.

i.e., you still don't get to bathe in the lake.


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## Beckis19 (Aug 20, 2010)

carebear said:
			
		

> ah, well then you should know that saponins will kill fish and all that good stuff, so even if you wash with real soap instead of synthetic detergent products you need to discard your soapy water away from lakes and streams.
> 
> i.e., you still don't get to bathe in the lake.



I've never bathed in the lake (esp when I've been to and seen some with leeches... :shock: ), I bathe at least 200' from any water source,  per Leave No Trace guidelines.  I at least did my research on THAT, lol....


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## ChrisShepp (Aug 20, 2010)

Beckis19 said:
			
		

> I was just sharing my spur-of-the moment urge to try experimenting, and I didn't think to stop to check the forum to see what would happen.  Actually, I had told my hubby about the idea, he has a chemical engineering degree (though he is now an environmental engineer) and I guess he didn't give it too much thought since he didn't say anything about it not working.  So I know next time I want to experiment to consult those who have actually tried/know  :wink:
> 
> No offence taken, but a little background, to help explain my madness:
> 
> I wasn't aiming to have the poo bar be my every-day shampoo.  Though it would be nice if I could find one that worked, like some people have.  I'm a backpacker, and wanted to see about making a bar soap I could use for my hair as well (though I have to admit, Dr. Bronners is an interesting read at times, lol...) that I can take with me.  I don't want to wash my hair and leave syndets all around the Great Outdoors.  I was aiming for something that I could tolerate using to clean my hair when it starts to get really nasty.  I didn't know I was voilating the 4 Great Laws of Soap  :wink:



Umbrella drinks after a long, hard day at work do make people type the strangest things, don't they?    I feel obligated to disclaim that although it looked my rant was directed at you, Beckis19, I was merely throwing my two cents into the general pot along with a healthy stir.


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## Beckis19 (Aug 20, 2010)

No problem, ChrisShepp...

Though I envy you your umbrella drink, I have an 8-month or so dry spell to live through before I can have my beloved Margarita on the rocks again.....


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## ChrisShepp (Aug 20, 2010)

Beckis19 said:
			
		

> No problem, ChrisShepp...
> 
> Though I envy you your umbrella drink, I have an 8-month or so dry spell to live through before I can have my beloved Margarita on the rocks again.....



Congratulations! When are you due?


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## Beckis19 (Aug 20, 2010)

April 17.


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## cwarren (Aug 24, 2010)

Soapmaker_CRO said:
			
		

> I need help on how to lower the pH of soap.
> 
> I have made a couple of natural soaps with lye and evan after 6 weeks PH is still around 10.
> I thought about using an acid to neutralize the base (NaOH), but I have not found an acid that is safe to use with NaOH that is also not deleterious to the skin. Also, I would like to know in which phase to add the acid or some other ingredient.
> ...


  I have learned to do zap test.. my book says ph of 7    sooo i was in a huge panic trying to get ph down ( before I found this site) and I threw out countless batches .. cause ph strips said 10 and 10.5 right after cutting  .. oh how frustrating................  goatsmilk will help lower ph if you are worried..


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## Dave D (Aug 24, 2010)

Soap doesn't strictly split back into fatty acids when the Ph is lowered below 8.0
Some of the fatty acids may split off the metal but not remotely close to all. To split all the fatty acids from the soap the ph would need to be lowered to about 4.5.
Furthermore week acids like citric, acetic, boric etc., are not capable of splitting all the soap/salt back into fatty acids. Weak acids lower the ph mainly by reacting with the free OH ions in the solution. When adding a weak acid to a salt an equallibrium is obtained that prevents all the fatty acids from being split. 
To split all the fatty acids from the soap a strong acid is required (sulfuric, nitric, hydrochloric etc).
Soap/salt is created around a Ph of 8-8.5, going above 8.5 does not indicate that more soap has been made only that there are OH ions present in the solution.

Ph is a tricky thing since Ph is the negative logarithym of hydrogen activity in a aqueous solution. It's largely related to the H+ or OH- concentration. 

My apologies to those that may be offended


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## carebear (Aug 24, 2010)

I think you mean "pH".  At least I hope so.

Why would anyone be offended by information?


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## Dave D (Aug 24, 2010)

carebear said:
			
		

> I think you mean "pH".  At least I hope so.


Yes, that's correct.



> Why would anyone be offended by information?


 I'm just not a wave maker by any means, especially as a newcomer.


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## veron (Nov 14, 2021)

I don't recommend it either, you avoid using a preservative with the basic pH.


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