Now I know most of us are usually working to lower the PH of our soaps from being to acidic. Usually adding something like citric acid to do so, which has worked well for me in the past as well. But from my understanding and experience, increasing the PH of a soap also increases its cleansing abilities. What is the suitable range for hand soaps? A PH of 9-10 is usually what I shoot for in all of my batches, but what would be the harm in going higher to 12 or even 13? What would one use to increase the PH, just increase the amount of LYE to the initial solution and limiting your superfat? Thanks in advance for any insightful advice! 8)
Increasing PH
- Thread starter cleangrip
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Saponista
Well-Known Member
Very high pH will result in skin burns so I would be very careful with this experiment.
Are you sure it's the pH itself that changes the cleansing, or the cleansing (from oil choice) that changes the pH? In other words, are you taking an affect as a cause?
First, people are lowering the pH from being too alkaline(opposite of acidic.) Too high a pH can damage skin and hair. It is not safe. It will also result in dry, tight skin that no one appreciates.
Like Craig said, more than pH affects cleansing. I use 100% coconut oil paste to clean bathrooms, dishes, stove, etc. The pH is low enough to not zap me, and it cleans well. I do wear gloves with it, though, because it just dries my hands out like no-body's business.
"...What would one use to increase the PH, just increase the amount of LYE to the initial solution and limiting your superfat?..."
If by "increase the initial amount of lye to the initial solution" means to use a more concentrated lye solution (say 40% NaOH rather than 28%), all that does is increase the rate of saponification. Limiting superfat doesn't work either. I've made soaps with as much as 40% too much lye. While these soaps were certainly high pH soaps for awhile, they were zap free soap after a couple of months. It's the nature of soap to reach a pH that is natural for it and stay there.
What is the harm of having excess lye in a hand soap? Sensitive, itchy, burning sensation. Redness, roughness, cracking. Eventually dermatitis or possibly chemical burns.
When I'm not playing mad scientist and instead am making soap for regular use in my home, I want to make a nicely formulated soap that has a pH normal for that particular blend of fats. If it's a laundry soap, I limit the superfat to prevent any excess fats in the finished soap (NOT to adjust the pH!) and I use a lot of coconut oil for fast dissolving and strong cleansing ability. If it's a bath soap, I formulate a soap that lathers well, is mild and safe for the skin, lasts a reasonably long time, and looks and smells nice.
***
For the record, adding citric acid does NOT lower pH UNLESS there is excess lye present. If there is no excess lye present, then the soap breaks down into fatty acids, releasing OH- ions to react with the H+ ions released by the acid. The pH remains stable as long as this fatty acid breakdown is going on. Keeping the pH stable despite the addition of acid or base is normal behavior for what's called a "buffered" system. That's what soap is -- it acts as a buffer.
Up to a point, this breakdown in a bar soap from soap to fatty acid is not perceptible to the user, but it's there. If enough acid is added, a bar soap will become soft, mushy, and greasy feeling. In a liquid soap, the breakdown is unmistakable -- there will be a layer of fatty acid floating on top of the soap.
If by "increase the initial amount of lye to the initial solution" means to use a more concentrated lye solution (say 40% NaOH rather than 28%), all that does is increase the rate of saponification. Limiting superfat doesn't work either. I've made soaps with as much as 40% too much lye. While these soaps were certainly high pH soaps for awhile, they were zap free soap after a couple of months. It's the nature of soap to reach a pH that is natural for it and stay there.
What is the harm of having excess lye in a hand soap? Sensitive, itchy, burning sensation. Redness, roughness, cracking. Eventually dermatitis or possibly chemical burns.
When I'm not playing mad scientist and instead am making soap for regular use in my home, I want to make a nicely formulated soap that has a pH normal for that particular blend of fats. If it's a laundry soap, I limit the superfat to prevent any excess fats in the finished soap (NOT to adjust the pH!) and I use a lot of coconut oil for fast dissolving and strong cleansing ability. If it's a bath soap, I formulate a soap that lathers well, is mild and safe for the skin, lasts a reasonably long time, and looks and smells nice.
***
For the record, adding citric acid does NOT lower pH UNLESS there is excess lye present. If there is no excess lye present, then the soap breaks down into fatty acids, releasing OH- ions to react with the H+ ions released by the acid. The pH remains stable as long as this fatty acid breakdown is going on. Keeping the pH stable despite the addition of acid or base is normal behavior for what's called a "buffered" system. That's what soap is -- it acts as a buffer.
Up to a point, this breakdown in a bar soap from soap to fatty acid is not perceptible to the user, but it's there. If enough acid is added, a bar soap will become soft, mushy, and greasy feeling. In a liquid soap, the breakdown is unmistakable -- there will be a layer of fatty acid floating on top of the soap.
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Thank you everyone for the replies! I based my knowledge of this article where it states in the lower portion:
http://www.newton.dep.anl.gov/askasci/chem00/chem00704.htm
"For body soap, a pH from 5 to 8 should be mild to skin. Higher pH values generally mean better cleaning of greasy and/or oily soils. A pH from about 8 to 10 seems fairly optimal for hand soap. If the soap is for laundry, a pH of 10 to 12 is acceptable"
As for how credible the source is, that could be debated. That's why I am asking here. From my experiments I've been using 100% coconut oil soap, some which have been lye heavy and some which were extremely superfatted. I honestly didn't notice much of a difference in after effect of either, but both were tested on heavily greasy hands. And the lye heavy soap cleaned much better. Although I haven't used it continually on a daily basis to see extended results on my hands, the initial tests indicated a much better cleansing effect to the more alkali soap. :Kitten Love:
http://www.newton.dep.anl.gov/askasci/chem00/chem00704.htm
"For body soap, a pH from 5 to 8 should be mild to skin. Higher pH values generally mean better cleaning of greasy and/or oily soils. A pH from about 8 to 10 seems fairly optimal for hand soap. If the soap is for laundry, a pH of 10 to 12 is acceptable"
As for how credible the source is, that could be debated. That's why I am asking here. From my experiments I've been using 100% coconut oil soap, some which have been lye heavy and some which were extremely superfatted. I honestly didn't notice much of a difference in after effect of either, but both were tested on heavily greasy hands. And the lye heavy soap cleaned much better. Although I haven't used it continually on a daily basis to see extended results on my hands, the initial tests indicated a much better cleansing effect to the more alkali soap. :Kitten Love:
Lye will bond with oils, so you could technically use Lye as a cleaner. You shouldn't, of course!
When making up a recipe in your chosen calc, look for a high cleansing number. I really do think that you are taking a correlation and calling it a cause - high cleansing soaps might well have a higher pH, but that does not mean that the pH is what is causing the greater cleaning power, rather it is the choice of oils.
When making up a recipe in your chosen calc, look for a high cleansing number. I really do think that you are taking a correlation and calling it a cause - high cleansing soaps might well have a higher pH, but that does not mean that the pH is what is causing the greater cleaning power, rather it is the choice of oils.
Saponista
Well-Known Member
That really effective oven cleaner is basically just potassium hydroxide gel so you slather it on and it turns the fat caked onto your oven into soap which you then just wipe away. It works like a dream.
I was reading that link. One of the posts had the following bit:
"It is practically impossible to remove enough of the sodium hydroxide from home-made soap to render it safe to use -- or to offer as a gift. It cannot be neutralized -- only "salted out" (at best, an unreliable removal process).
I agree, the tongue test is dangerous. The alkali would make short work of one's tongue."
That sounds exactly like something I read when I was still a new soaper. Good thing I had y'all to ask and learn better.
ETA-For the record, NaOH soap is perfectly safe if made properly, and zap testing a soap made using a reliable lye calculator is no more dangerous than brushing your teeth.
"It is practically impossible to remove enough of the sodium hydroxide from home-made soap to render it safe to use -- or to offer as a gift. It cannot be neutralized -- only "salted out" (at best, an unreliable removal process).
I agree, the tongue test is dangerous. The alkali would make short work of one's tongue."
That sounds exactly like something I read when I was still a new soaper. Good thing I had y'all to ask and learn better.
ETA-For the record, NaOH soap is perfectly safe if made properly, and zap testing a soap made using a reliable lye calculator is no more dangerous than brushing your teeth.
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I remember seeing that same quote on the interwebs, too, and wondered if the person who made the quote had ever made any soap before in their life. Obviously not, from the sounds of it....or at least not any good soap anyway.
IrishLass
