In heating fats for an extended period of time, when do ALEs begin to occur in the fat(if at all)? I once roomed with a chinese guy in school who simmered meat for multiple days, then sat down and ate the whole thing. I recently 'rendered'(albeit poorly) trimmings of beef fat(tallow) from the butcher's and left it in a pot overnight on approx. 100 degrees F. Upon taking it ouot it had a bit of crusty brownishness to it. Would heating fats for this long(approx. 11 hours) create Advanced lipoxidation end-products(ALEs)? If so, what can be done to prevent this while rendering fat? Any feeedback would be appreciated. P.S: soon I will be terminating usage of electricity. Any feedback on how to render fat(eg. with what equipment if any; battery-powered, etc.)?
This is controversial, but my expectation is that exogenous ALEs are about as important as exogenous cholesterol: i.e. hardly at all. I only worry about endogenous ones. In both cases the key is to minimize exogenous sugar.
Stearic acid is a very stable saturated fatty acid. The melting point and boiling points are very high, among the highest of fat molecules so I don't think you have to worry about ALE's at 100 degrees.
69.6 °C, 343 K, 157 °F
383 °C, 656 K, 721 °F
I'd say you're operating safely well under the temperatures at which oxidation may occur in stearic acid.
Stearic acid (first syllable pronounced either steer or stair) is the saturated fatty acid with an 18 carbon chain and has the IUPAC name octadecanoic acid. It is a waxy solid, and its chemical formula is C18H36O2, or CH3(CH2)16COOH. Its name comes from the Greek word στέαρ ("stéar"; genitive: "stéatos"), which means tallow.
The crusty brownishness on top is what you call "pork rinds" when you're rendering lard. I guess it's beef rinds for tallow. Totally normal (and delicious). If it's burned and blackened, I wouldn't eat it, but I think what you got was normal. How did the tallow itself taste?
PersonMan, If you are cutting off all electricity, then I assume you are not in the middle of a city? If so, I would suggest going back to the old way - a dutch oven suspended over a fire out back with some kind of screening (NOT aluminum or galvanized) to keep out the bugs. No lid because you don't want steam condensing and running back down into the fat. Raising or lowering the height of your pot will control the amount of heat so you should be able to figure the rest out just fine. Otherwise, I think you will be expending way too much of your now valuable battery power on this. And then how will you power your computer to visit Paleohacks? ;p