Re-visiting Chicken Fat

cmzaha said:

Calling TOMH and/or DeeAnna or anyone else that has an idea why. Per another posting I mentioned using Chicken Fat with a high tallow, lard recipe. Recipe follows. I made identical batches no fragrance or additives using chicken fat in one batch with cherry kernel in place of chickie fat and one with olive replacing chickie fat soaping with the same lye concentration of 34% and same room temp oil and lye. The only batch that took forever to trace is the batch with 10% chickie fat. I was thinking the linoleic fatty acid of the chicken fat, but cherry kernel has more linoleic but also has linolenic which chicken fat does not have according to soapcalc. Nope I have not looked up the actual profile of each. Maybe someone smarter than me can figure out what is slowing the trace. I still do not know if the soap is going to come down with dos.

Recipe:
Tallow 60%
Lard 15%
chicken fat 15%
Coconut oil 5%
Castor 5%
Lye Concentration 34%
Superfat 3%
Made with papaya puree

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topofmurrayhill said:

I don't know the answer. I can only share one speculative thought.

An oil can be characterized by its fatty acid composition, like the percentages shown in SoapCalc. It can also be characterized by its TAG composition, meaning how those fatty acids are distributed amongst the oil molecules (a.k.a. triglycerides, triacylglycerols or TAGs).

Each oil molecule has three fatty acids, so they can occur in many different combinations. Besides the FA percentages, the most common combinations of fatty acids in the TAGs is characteristic of a particular oil. Maybe this affects trace speed as well. The TAG composition of chicken fat is similar to that of lard, which is another slow tracer.

The percentages in the recipe make me doubt this explanation, but that's all I've got. Fatty acid percentages for animal fats can vary a fair amount, but various sources are reasonably consistent about chicken fat.

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galaxyMLP said:

It could also relate to the free fatty acid (FFA) amount. Are you getting the chicken fat yourself from chicken you cook?

If the chicken fat is being prepped by you and is very fresh it could also have to do with the FFA amount. FFA's react instantly with lye unlike triglycerides and they don't produce glycerin. Older oils will have a higher FFA amount. Any packaged oil is going to be older than freshly prepared chicken fat but they way you process the fat may also contribute to FFA contents that are lower or higher.

High heat and water with agitation to render the fat will increase the FFA concentration whereas a low, dry heat source will decrease the likely hood of them.

Just another thought.

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galaxyMLP said:

I guess it's possible. Since FFAs have a rather large impact on trace time it would surprise me that much. Stearic acid isn't the best example because it needs to be used at such a high temperature but it accelerates trace extremely quickly. I wonder if you add 1% stearic acid into OO, melt it, and then cool it and used that to make a soap what the difference in trace time would be. Maybe I'll try it.

Other thoughts could be the nature of unsaponifiables in the cherry kernel/olive/chicken.

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