CathyB
Well-Known Member
I've seen so much information on using leaf/kidney fat for soap, and other information saying fat is fat, use it all.
I've been using all fats, just combining and rendering. But now I want to know more.
I've found this tidbit:
"The difference between hard muscle fat and kidney fat may not be all that apparent up front. They both can be quite stiff and look much alike. The real difference can seen during and following the rendering process.
Suet, as opposed to muscle fat, contains a higher level of a triglyceride known as glyceryl tristearate, otherwise known as stearin. The result is that suet has a higher melting point and congealing point than regular fat."
Source: Suet, Part two: What it is, What it isn’t, and What to Look For
From one of DeAnn's brilliant posts I find
And from Properties of soapmaking oils | Summer Bee Meadow | Handcrafted Soaps, Soapmaking knowledge and supplies for crafters I learned that Steric Acid is responsible for "Hard, long lasting bar, stable lather."
In terms of soapmaking, where does the preference for kidney/leaf fat come from? Is it related to the rendering process, or is there an actual biological/chemical basis for the preference?
In practical terms, has anyone experimented using just leaf fat and just body fat and found any differences in soap qualities?
I've been using all fats, just combining and rendering. But now I want to know more.
I've found this tidbit:
"The difference between hard muscle fat and kidney fat may not be all that apparent up front. They both can be quite stiff and look much alike. The real difference can seen during and following the rendering process.
Suet, as opposed to muscle fat, contains a higher level of a triglyceride known as glyceryl tristearate, otherwise known as stearin. The result is that suet has a higher melting point and congealing point than regular fat."
Source: Suet, Part two: What it is, What it isn’t, and What to Look For
From one of DeAnn's brilliant posts I find
Stearin is about the same as any other soap making fat as far as the amount of glycerin created when it's saponified. You can calculate it: Soapy Stuff: Glycerin made by saponification
Stearic acid is made by further processing stearin to break the fat molecules apart into glycerin and fatty acid molecules. The glycerin is removed and the fatty acids that remain are either sold as commercial grade stearic acid, which is a mix of mostly stearic and palmitic acids, or further refined. Stearic acid adds no glycerin when it saponifies.
And from Properties of soapmaking oils | Summer Bee Meadow | Handcrafted Soaps, Soapmaking knowledge and supplies for crafters I learned that Steric Acid is responsible for "Hard, long lasting bar, stable lather."
In terms of soapmaking, where does the preference for kidney/leaf fat come from? Is it related to the rendering process, or is there an actual biological/chemical basis for the preference?
In practical terms, has anyone experimented using just leaf fat and just body fat and found any differences in soap qualities?