Understanding the basic anatomy of one mammal—a cow, a pig, a woolly mammoth, or a rabbit—will help you develop an instinctual sense for which cuts of meat to use in almost any situation.
Most of us already have a general awareness of how animals move, and, in order to determine which cuts are which, it's helpful to think about how certain muscles may have had to work throughout the animal's lifetime: Was it a hard-working, high-activity muscle (legs, cheeks), or a lazy, low-activity muscle (back, loin)? If you can answer that question, it will help you determine how long to cook it, and at what temperature, in order to achieve a whole range of results. In general, muscles that work harder will be tough, while muscles that work less will be tender. Read on to familiarize yourself with tough and tender cuts, so you can head to the butcher confident in your protein-picking prowess.
What Makes Meat Tough or Tender?
Muscles that work hard have a lot of collagen. Collagen (and a little elastin) keep the muscles together and attached to the bone. So it's not surprising that hard-working muscles need a lot of collagen to do their job, or that this collagen makes them tough. But given enough time, heat, and moisture, this collagen will transform into gelatin. And gelatin and melted fat give slow-cooked tough cuts like smoked brisket their wonderful succulence. (More on that here.)
Take cows, for example. Cows spend much of their time chewing, so their cheeks develop a lot of tough collagen. To make those cheeks tender, you need to cook them for a long time at a low temperature, like 140 °F / 60 °C for 72 hours, or for an hour in a pressure cooker at 250 °F / 121 °C. Likewise, beef shanks, chucks, and rumps do a lot of work, and need a lot of time or heat to get tender. But the muscles in the middle of the cow's back don't do much at all, so that's where you find tender, juicy cuts like filet mignons and NY strip steaks.
A great way to memorize which muscles are tough and which are tender is to remember that, beginning with the center of the cow's back, and moving down and outwards along its body from there, the muscles go from most tender to most tough, as we illustrate below.
Using Your Animal Instinct
What's true for cows is true for other four-legged animals. Their necks, legs, shoulders, and butts do the hard work, so cuts from those areas will have a lot of collagen. Cuts from ribs and backs will have less collagen, and will be more tender. This means that a time-and-temperature combination that works for beef shank, like 176 °F / 80 °C for 16–24 hours, will also work for lamb, venison, antelope, buffalo, reindeer, and mammoth shanks too.
If you're not sure what part of the animal a cut in the store came from, there are some clues you can look for: a coarse grain usually means there's more collagen, as does multiple muscles in the same cut. And—this may comes as a surprise—lots of marbling usually means you're looking at a tough cut. Hardworking muscles like the shoulder and the rump are optimized to store fat as energy that they can later burn during the sort of prolonged, arduous activities that tender parts like chicken breast or pork loin aren't built to endure.
What Does It All Mean?
It means that you can use the same time and temperature combos for the same cuts of meat, no matter which mammal you're feasting on. So when Uncle Jake brings you a moose shoulder on New Year's Eve, you can treat it the way you did last week's lamb or pork shoulder. Set your water bath to 140 °F / 60 °C, cook that thing for 24 hours, and get ready for the feast of the year.