Soap Chemistry Questions

[MrT]

Hey all

So, in dribs and drabs over the past few months I've been reading about how soap is made, and I have a few outstanding questions I would like you to clear up.

1) rendered fat is a mixture of fatty acids yeah? And different fats have a different ratio of the different acids (plus glycerine)? So for example, in theory if you mixed all the different acids in the correct ratio for tallow (so stearic acid, oleic acid etc etc), would the soap perform identically to if you just used tallow? Or is the whole more than the sum of the parts?

2) From what I have read, commercial stearic acid is generally made from tallow by separating the acids (the first stage of saponification). So how can most "vegan" soaps get away with calling themselves vegan when they almost all have stearic acid added? Vegan foods aren't allowed to use gelatin, and I feel like this is analogous.

3) is Sodium Tallowate and Potassium Tallowate actually a thing? It feels made up. Because chemically speaking, tallow isn't a fatty acid but rather a mixture of acids. So when you mix the sodium hydroxide with tallow the acids split and are neutralized by the alkali and you get sodium stearate, sodium oleicate (or whatever it would be called). But sodium Tallowate? Really? The only thing that I can think of is that by Sodium Tallowate they mean the ratio of different salts (sodium stearate etc) that would occurs when mixing tallow with the alkali.

I think that's all I have for now. I may come back with more later. Looking forward to someone with much more chemistry chiming in. I assume @Anthony or @Barrister and Mann have some solid answers.

 

[filobiblic]

@alfredus is our resident Chemist... [emoji11]

 

[Nick the Knife]

1) No idea sorry.
2) As with much of the soap making industry Palm oil is often used for the same things tallow is. So I know some stearic is made from PO.
3) I'd have agreed with you that it was 'lazy' labelling but Wikipedia etc say it's an actual scientifically defined substance and I assume the regulatory authorities feel the same way - hence it's ok to put on the labels.

 

[alfredus]

OK, I will try my best - although I haven't worked in the industry for more than 6 years and never had any experience with soap making...

1: in theory YES, BUT: usually natural products contain 100's, 1000's or many more compounds. And natural compound synthesis/analysis in IMO the pinnacle of organic chemistry. So the reality is, you rarely know 100% the composition of a natural compound and therefore can't say what the small amounts of unknown actually do.

Very well known examples are for example Vanilla: artificial the original compound consists of many many (aromatic) compounds and artificial Vanillin is just one of them. Better ones are maybe a mixture of 5 compounds, but nothing beats the real deal.

So yes, you could in theory make Tallow by mixing all its components, but it would be a very expensive project, if you want to get the real deal.

2: again without knowing the details, in theory you could get it from other fats, like coconut - but of course it would be way more expensive. Having said that, the food labelling in Australia is a joke, very few names are actually defined and protected. So if you want really a vegan products - and again I would imagine the price to be much more expensive - I would get them from countries with decent labelling laws, and do some research.

IMO: I think it is fantastic, that we use tallow something, rather than wasting it. I understand, if you are a vegetarian/vegan out of health or morality. However using the whole animal is actually a good thing, and as long as other people eat meat, you should at least support the usage of the rest of the animal...I hope my moral point of view makes sense.

3: you are absolutely right. But again (see point 1), as you don't know 100% the composition of the tallow, it is hard to give 100% the composition of the resulting chemical process.

Hope this helps a bit

 

[MrT]

OK, I will try my best - although I haven't worked in the industry for more than 6 years and never had any experience with soap making...

1: in theory YES, BUT: usually natural products contain 100's, 1000's or many more compounds. And natural compound synthesis/analysis in IMO the pinnacle of organic chemistry. So the reality is, you rarely know 100% the composition of a natural compound and therefore can't say what the small amounts of unknown actually do.

Very well known examples are for example Vanilla: artificial the original compound consists of many many (aromatic) compounds and artificial Vanillin is just one of them. Better ones are maybe a mixture of 5 compounds, but nothing beats the real deal.

So yes, you could in theory make Tallow by mixing all its components, but it would be a very expensive project, if you want to get the real deal.

2: again without knowing the details, in theory you could get it from other fats, like coconut - but of course it would be way more expensive. Having said that, the food labelling in Australia is a joke, very few names are actually defined and protected. So if you want really a vegan products - and again I would imagine the price to be much more expensive - I would get them from countries with decent labelling laws, and do some research.

IMO: I think it is fantastic, that we use tallow something, rather than wasting it. I understand, if you are a vegetarian/vegan out of health or morality. However using the whole animal is actually a good thing, and as long as other people eat meat, you should at least support the usage of the rest of the animal...I hope my moral point of view makes sense.

3: you are absolutely right. But again (see point 1), as you don't know 100% the composition of the tallow, it is hard to give 100% the composition of the resulting chemical process.

Hope this helps a bit

Yep. Thanks mate. Makes sense, especially the last one.

And for the record I'm not vegan or vegetarian and have no problems with tallow soaps. And I agree with you that using the whole of the animal is a very good thing. I'm just curious as to how they can call it vegan soap.

As NtK said, I'm sure you can make stearic acid from other fats, but didn't think they did. So to call a soap vegan you should have to avoid adding stearic acid, or be confident of its origins.

 

[bald as]

Hi @MrT the answers @alfredus gave cover most of what I feel about soap making. I confess I don't know a whole lot. I understand the basic chemistry and a bit more but the individual component parts of the various oils and fats contribute significantly more than just the known fatty acids etc.
While you could possibly make a workable shaving soap from just Tallow you can make a much better shaving soap from tallow plus other ingredients. As far as I'm aware the Stearic Acid I use is plant derived from Palm Oil [I think] Tallow has a a reasonable component of Stearic acid itself but for shaving soap in most cases Stearic Acid is added to help generate a much better creamy lather. I have found it is a balancing act to achieve a creamy lather that isn't all bubbles. Again that comes back to the interaction of the Sodium and Potassium salts generated by the saponification process and the fine balance of other oils and the unseen, to me at least, chemical reactions between lesser components of the constituent oils and fats.

The beauty of the whole process is that it is very straight forward and to make good soap at home only a rudimentary knowledge of chemistry, safety and ingredient combinations is required as the addition of a strong alkali to fats just wants to make soap.

If you haven't tried making a soap it is a most rewarding "primitive" achievement. I seriously didn't think I could make soap but the soap actually made itself.

Be careful you are not afflicted with SMD [SoapMakingDissorder] I liken it a bit to brewing n All grain beer. Takes time and thought but the rewards are useful But there is always some little thing you can do to improve your soap - or beer.

Steve

 

[glenos]

@alfredus is our resident Chemist...

Actually, there are two of us.

Be careful you are not afflicted with SMD [SoapMakingDissorder] I liken it a bit to brewing n All grain beer. Takes time and thought but the rewards are useful But there is always some little thing you can do to improve your soap - or beer.

I agree, I had a crack at making a batch of soap once, when I had a lot of apricot kernel oil, it came out a bit too soft, needer some longer chain fats to harden it up. It was also funky because the oil wasn't very clean, I had only given it a basic filter.

Making all-grain beer now that is something I can talk about, although I am a beginner.

 

[bald as]

I started making beer in 1969 and all grain in about 1996 - excellent fun.