penelopejane
Well-Known Member
^^^ post 37hiw can that be when Johnsons baby soap is the least irritating but the highest pH?
PH reduction
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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
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.
ngian
Well-Known Member
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/
http://thealabublog.com/2010/05/6-reasons-why-people-use-oatmeal-in-soap/
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)
"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.
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.
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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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.
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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ngian
Well-Known Member
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
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.
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
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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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
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
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
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
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!
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.
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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You will need to use some sort of emulsifier. I do not use them, but I think IrishLass' favorite is PS80.
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
....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
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.
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.
