Question to the science nerds.

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Soapprentice

Soapprentice

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I read in few threads that the speed of trace depends on how fast lye molecules react with fat molecules. Clearly olive oil and coconut oil take a long time to trace. So, I am guessing that the lye takes a while to bind with these particular oils. So, here is my question: lye reacts to which oil faster? Olive or coconut. I ask this because I want to try 70% coconut and 30% olive oil with 20% SF. I want CO to be the SF as I imagine OO as SF at 20% is not going to be a good soap.. is that even possible? I seriously hope this makes sense.
 
Not only that, but why should a soap with the 20% co sf be better than olive oil? The superfat is there in this case to provide some oil for the soap molecules to bind with, stopping them from bonding with the natural oils on your skin (which makes the soap less stripping) - so if the soap molecules are bonding with co or oo molecules, I'm not sure that it would be so different in practice
 
The Efficacious Gentleman said:
Not only that, but why should a soap with the 20% co sf be better than olive oil? The superfat is there in this case to provide some oil for the soap molecules to bind with, stopping them from bonding with the natural oils on your skin (which makes the soap less stripping) - so if the soap molecules are bonding with co or oo molecules, I'm not sure that it would be so different in practice
Click to expand...

I was thinking that as coconut oil is less greasy, it would result in better shower experience. Am I wrong?
 
Well that assumes that the soap binds with oils on your skin, removes them, and replaces them with the superfat oil. As we know, we use a higher superfat in a 100% co soap, not because it will leave more of that oil on your skin but because there is more oil in the soap for the soap to bond with rather than the oil on your skin. Which is the reason why a 100% co soap is then not so harsh, a lot of the "stripping power" has already been bound to the oils in the superfat meaning there is less stripping power to bind with the oils on your skin.

But if you still want to think of it the other way - even though the lye will react with the co faster, it WILL still react with the olive. As the majority of your recipe is co, I would say that the majority of your superfat is likely to be coconut
 
The Efficacious Gentleman said:
Well that assumes that the soap binds with oils on your skin, removes them, and replaces them with the superfat oil. As we know, we use a higher superfat in a 100% co soap, not because it will leave more of that oil on your skin but because there is more oil in the soap for the soap to bond with rather than the oil on your skin. Which is the reason why a 100% co soap is then not so harsh, a lot of the "stripping power" has already been bound to the oils in the superfat meaning there is less stripping power to bind with the oils on your skin.

But if you still want to think of it the other way - even though the lye will react with the co faster, it WILL still react with the olive. As the majority of your recipe is co, I would say that the majority of your superfat is likely to be coconut
Click to expand...

I see you point. Thank you for this perspective. :D
 
Soapprentice said:
I was thinking that as coconut oil is less greasy, it would result in better shower experience. Am I wrong?
Click to expand...

I think of CO as very greasy or very oily, whichever it is, to me it seems to be much more oily than some oils when I have to do the clean-up. As for a shower experience, I can't say. High CO percentages in soap are too drying to my skin, so I don't usually use much in my recipes.
 
I think The Gent has a point based on a general trend that Kevin Dunn reported from some of his soapy experiments. Dunn found a higher % of unsaturated fatty acids in the superfat than in the original recipe.

If this trend applies broadly (and I do not know if it does!!!), then the superfat in your soap might be something more like 60% CO fatty acids and 40% olive fatty acids if your recipe is 70% CO and 30% olive. But that's just an educated guess, not for certain.
 

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