This could fit into Chemistry, Seasoned Advice or other SE forums. The largest number of "close" questions seems to be here; apologies if I'm in the wrong place.

I've noticed when cooking some meats - most notably real mutton, from older sheep - that quite a bit of fat renders out long before the meat is cooked, while some remains even after high-temperature grilling or sautéeing. When working with ground meat (patties/burgers, sausages, patés), the effect seems more dramatic, with a distinct separation in fat release between two rendering-temperature ranges.

Assuming that the phenomenon is real, and not an experimental or observational artifact, can someone here explain the cause? Some possibilities:

  • Distinct populations of fat types, whether by glyceride number, aliphatic chain length, cis/trans isomers, mixed within each fat-body?

  • Anatomically distinct (perhaps microscopic) fat bodies with different functions, hence compositions?

  • Other anatomic factors, like encapsulation of fats with varying degrees of containment by membranes or other structures?

As a cook, one often wishes to maintain high fat content. Expensive Wagyu ("Kobe") beef must be cooked very lightly to retain all the marbling. And there are many distinct ways to cook hamburgers to retain fat while adequately cooking the meat for safety and organoleptic properties. So insight into this kind of melting/rendering behaviour might be useful in recipe design and execution, in the same way that making puff pastry requires careful temperature control when mixing fat into détrempe and beurrage, as well as paste temperature during folding/rolling.

Thanks for any thoughts.

  • $\begingroup$ Not going to answer formally because I don't have the ambition to research this. My guess is that it's a combination of factors, including anatomic factors (encapsulation of fats with varying degrees of containment by connective tissue) and physiologic, i.e. we make a number of fats, some that melt at lower temperatures and higher temperatures and everything in between, and maybe you're noticing two of the more common triglycerides melting. I used to make soap (a lot for a long time) and rendered fat from everything from deer/goats to bears ( lots of hunters around here)... $\endgroup$ Commented Mar 4, 2023 at 20:58
  • $\begingroup$ ...and there was definitely a range of fats in any one animal fat, and definitely some encapsulation such that pulverizing was necessary to get it. Interestingly (or maybe not), the same is true of plant fat production: it's not just one kind of fat. Sometimes there is a very wide mixture that includes fats that are liquids at room temperature right to fats that you need a chisel and hammer to break up at room temperature (these would be long, very highly saturated fats. Pure coconut oil can be fractionated into several groups with different melting points, one a liquid, another a goop, etc.) $\endgroup$ Commented Mar 4, 2023 at 21:11
  • $\begingroup$ One last comment. Adult sheep have seen more extremes in temperatures than lambs. Animals produce different fats in cold temperatures than in warm. Maybe you're seeing this phenomenon as well. If there were an Organic Chemistry site, this would be a good fit there, I think. $\endgroup$ Commented Mar 4, 2023 at 21:17


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