question on super fat

[Wyndham Dennison]

I have come to understand the reason for a common 5% superfat in soap making . My 2 q1uestions(based on a video from soaps 101 channel) is about when to or( not to) add the superfat after trace and what oil to add.
If I calculate a batch for 5% oil reserved until trace, would it make any meaningful difference if the reserved oil was a blend of all the oils, a reserve of one of the oils, like hard or soft oil or lastly a different oil not in the base for some special feature, example 5% rice bran oil(just picking a name out of the hat).

In another thought on oil/water,Soapcalc has a starting default 38 % water to oil. Should this ratio be based on any certain characteristic of the oils used such as hard/soft oils used in a batch or other things I'm not aware of.
Thanks for any thoughts

 

[szaza]

Adding an intended oil for superfat at trace will probably not really make any difference in the resulting soap, since the soap is still saponifying and the lye will take whichever oil it prefers to react with.
It is possible to add a superfatting oil after cook in HP, because saponification is supposed to be complete at that point, but even that is a bit up for speculation as the soap probably still reacts further in the mold.
As to the amount of water, most people here use a lye concentration (either in percentages or lye:water ratio). The reason is very well explained here

 

[DeeAnna]

I'm going to point you toward several articles I've written rather than write a detailed reply. Just saving time answering these questions, since they're asked a lot.

superfat and adding stuff at "trace" -- https://classicbells.com/soap/superfat.asp

"water as 38% of fats" vs other ways to calculate water -- https://classicbells.com/soap/waterInSoap.asp

 

[Todd Ziegler]

You have it backwards just a little. Superfat is the amount of that doesn't saponify. In other words, if you have a 5% super fat then 5% of your oils will remain as oil and not turn into soap. Some oils have a low sopanifiable content and they are used for their inherent qualities and not for cleaning/cleansing. If you look at a good soap oil chart it will help you decide which oil you want to use and how much of it will turn into soap.

 

[Wyndham Dennison]

DeeAnna, those were excellent , understandable articles and cleared the air for me on these issues. Also, thanks all for good advice from others here posting.
Pardon me for getting into the weeds, as it were, about these issues but I've been a potter for over 30 yrs, making and firing my own pottery with glazes that I have arrived at through yrs of filtering through good and bad information .
Just as a side note. When I was about 10yrs old, my father and mother had a c country grocery store with a full meat butcher shop. The woman who looked after me, would take the tallow, renderit down in a20 gal wash tub over a wood fire, add Red Devil lye to sell in the store for extra money. that was some tuff @%#@, would get anything clean .But I digress, Thanks

 

[jcandleattic]

would take the tallow, renderit down in a20 gal wash tub over a wood fire, add Red Devil lye to sell in the store for extra money. that was some tuff @%#@, would get anything clean

Yep, she was making old fashioned "lye soap" (usually when the older generation asks for "lye soap" this is what they are talking about) The only thing she actually did wrong was she probably just didn't take the SAP value of the lard into consideration, and probably didn't let it cure properly.