Would have given the same advice as
@Johnez if I weren't sound asleep at that time
. I love time zones!
Maybe an addition to this is that when you are aiming for soap, you don't have to make the detour to triglycerides. It's much easier to get hold of the free fatty acids ad good purity; if you want to make a soap “as if” it were made from pure triglycerides, just use those, neutralise with NaOH (hot process), and add 7.7 g of glycerol per 10 g of NaOH.
Reasonably pure lauric/myristic/palmitic/stearic/oleic acids are quite readily available as FFA (e. g. as M&P base ingredients). PUFAs (linoleic/linolenic) not so much, but high-PUFA soap (like from pure HL sunflower or safflower oil) has its own issues, and isn't worth the hassle IMHO (Remember the 100% canola soap? That's only some 27% PUFA, imagine how four times that PUFA amount would work out…). For ricinoleic acid, use castor oil as-is.
But this brings us to another major issue with your question: it is hard to predict FA blends from comparing/extrapolating single-FA soaps. Best example: castor. As little as
20%, let alone
100% it can ruin lather, and nothing indicates the miraculous effect that 3…6% of it does to an oil blend. Or hardness: a mostly-oleic castile soap hardens up nicely. Why bother adding saturated FAs at all? Or, on the contrary, all fully-saturated soaps are rock hard. Which one would qualify best to harden up a soft-oil recipe? Making a high-stearate soap is impossible with CP,
a literal pain even with HP – how could people be bothered at all to work with stearic acid? Which FA does affect lather in a positive or negative way? How to judge skin feel? What about superfat, unsaponifiables, minor fatty acids?
In short: as appealing as this idea sounds, it poses more question than it answers. It is more insightful to take an established formula, and tweak the ingredient percentages to modify single FA content by a few %, and compare these, to understand what properties the FAs affect
at typical usage rates.
Side note: It sounds like you are having bar soap in mind. That actually poses a pretty severe limitation on what can be done recipe-wise (to get something that can be used like soap). In fact I have done something as close to single-FA as possible from household means, but for
liquid soap (incidentally escalated from a comment of
@Johnez – geez, always the same names…). There you don't need to hope for a bar to solidify, the PUFA margins for rancidity are not as tight, and heat can convince insoluble components (like stearate soap) to report. Even then, the interferences between FAs are complicated enough (viscosity thinning by coconut and castor, turbidity, lather thickness and longevity, foamer bottle performance).
