Is cold process and hot process soap live up to its skin benefits claim?

Formulating

Is cold process and hot process soap live up to its skin benefits claim?

Posted by cindychums on January 31, 2018 at 5:14 pm

Hi my name is Cind and I consider myself a newbie (have been making for a year) in soap making. I’ve been taking cosmetic scientific courses in the meantime. The soaps I’ve made are by cold process so far, friends and family love them. However, the more I look at the science behind soaping, the more curious I am about the benefits of the soap every soaper claims.

I know soap making involves a chemical reaction called saponification where fats/ oils react with sodium hydroxide (lye) and results in glycerin and salt (soap). Are the benefits (such as vitamins) in the courier oils to start off with in the soap making process will remain after saponification? Also the moisturising/ skin softening characteristics are contributed by the fatty acids of each specific carrier oil, after going through saponification process, will these characteristics still remain in the soap? What would be the chemical reaction say an end product pure olive oil soap (100% olive oil + lye to begin with) has gone through?

These might be obvious to experienced soap artisans but please pardon my ignorant comments.

Cind

cindychums replied 6 years, 9 months ago 4 Members · 8 Replies
8 Replies

Jennova

Member
January 31, 2018 at 5:36 pm

Oils are saponified via a hydrolysis reaction… I’d imagine that many of the skin benefits from oils are damaged via the reaction, but perhaps someone else can tell you with more confidence. Oils with different constituents will definitely have an impact on the qualities of the bar, e.g. coconut oil -> more cleansing, fluffier lather, olive -> softer bar, more conditioning. With all of that said, cold/hot process soaps are also quite alkaline, which can, in turn, be quite harsh on your skin… which may negate the skin benefits from the bar compared to a syndet bar. Interested to hear other peoples opinions!
OldPerry

Member
January 31, 2018 at 5:47 pm

Vitamins don’t actually provide any consumer perceptible benefits when delivered from soap (or syndet bars either).

There will be a certain amount of the initial oil that does not chemically react and that can have an impact on the aesthetics of the soap bar.
DRBOB@VERDIENT.BIZ

Member
January 31, 2018 at 10:34 pm

The skin irritation from most any alkaline soap is due to the PH which overrides any oils butters/vitamins etc for skin benefits.You can blend for some mildness for example 80/20 Tallow/coconut is milder than 70/30 and/or you can reduce Ph by superfatting ie add 1-5% stearic acid to lower the PH. A rule of thumb -the higher the alkyl chain length the milder but the trade-off is you lose lather.
cindychums

Member
February 1, 2018 at 9:21 am

Thanks Jennova ,Perry and DRBOB@VERDIENT.BIZ .

Jennova - yes, different constituents of oil imparts its own sensory characteristics to the bar.

Perry - yes, agree that Vitamins don’t perceived as benefits to customers in cold processed/ hot processed soap, but do they still exist in the bar after going through saponification? Of course we take into account the temperature of the vitamin doesn’t get destroyed by the heat during the soap making process.
Also agree with you that the initial oil that doesn’t chemically react (superfat, the extra oil remains in the bar) can have an impact on the touch and feel of the soap bar

DRBOB@VERDIENT.BIZ - I believe too that the alkaline pH has a negative impact on skin barrier. So aside from superfattening the soap by adding extra oil, adding stearic acid (fatty acid) could be another way to go, or do both at the same time? I’d imagine after adding stearic acid the bar will be much harder other than losing the lather. How much pH were you able to lower it down to?
DRBOB@VERDIENT.BIZ

Member
February 1, 2018 at 4:16 pm

Addition of stearic acid at 1-5% lowered bar Ph from 10-10.5 to 8-8.5.Does make a firmer/harder bar but you can raise water slightly (1-2%) to compensate if needed.Another way is to add 1% hydrolyzed oat protein to get perceived lather boost and skin feel Doing both may give you what you are looking for.although never added HOP to superfatted bar i have done it on regular 80/20 Tallow/coco and consumer tested on at least 500 subjects both in US and abroad with positive results in double blind crossovers.
OldPerry

Member
February 1, 2018 at 7:27 pm

I don’t know all the reactions that would be involved with vitamins blended with sodium hydroxide. As you can see in the link, Ascorbic Acid (vitamin C) reacts with NaOH to form Sodium Ascorbate which in water just dissociates into Vitamin C so it doesn’t change much.

Vitamin C reaction

The same would happen with other acid vitamins like Retinoic Acid. Non-acid vitamins probably wouldn’t react much during the saponification reaction.

My point is that it doesn’t really matter whether the vitamin gets “destroyed” during the reaction though. Whether it is “destroyed” or remains intact, consumers will not notice any difference in the performance of the soap or the condition of their skin afterwards.
cindychums

Member
February 3, 2018 at 3:14 am

Thanks DRBOB@VERDIENT.BIZ for the suggestions. I’ll try all you suggested. I wonder if ever possible to lower to pH 5.5 to make an acidic bar of soap, I know it jus denies the law of chemistry and probably will result in liquid soap, only if it’s still a “soap” technically speaking. I don’t mind using liquid soap as long as it doesn’t damage my skin and still retains the goodies of the original oil.

Perry , thanks for the awesome explanations. You’re right about the consumer appeals,
cindychums

Member
February 3, 2018 at 3:17 am

Sorry repeated post by mistake