"How do you like your steak?"
It depends 100% on the cut. A filet with little to no fat on it should absolutely be cooked rare (<130F). Counter-intuitively, the lower quality the meat, the less fat it will have and therefore the more important it is that it be cooked Rare. Conversely a Wagyu filet (with a TON of fat marbling) could be cooked medium well (150F) and still taste absolutely delicious because the fat will keep it tender. I would personally argue it should be cooked Medium-Rare to Medium (137F) and not Rare (130F), because we want that fat partially rendered.
Similarly, other cuts like a Prime Ribeye with a ton of fat on it are also best cooked to Medium (140F). Rare to Medium Rare just doesn't render the fat enough and we can end up with a slightly rubbery texture for certain bites.
"My Michelin Chef serves Ribeye rare."
Now we get into Time. A High End Steakhouse might sous vide their Ribeye for 4 hours at 130F then hit it with a blowtorch and serve it immediately. This would technically be "rare" BUT they still managed to render a bunch of fat. Chef might say, "Order it Medium Rare" because he gets the rendering from the fat and the 132F serving temp gives him some wiggle room to get a good crust with the torch.
Most places though are probably doing reverse sear or forward sear and that's where the Medium comes into play. We want a little extra time in the oven / smoker / drawer to render that fat.
Then of course we have BBQ meats, like Bristket or Ribs or Shoulder. These cuts we cook WELL PAST Well Done (165F) , for hours and hours and hours, up to 200F+ until the hard thick fat has just completely rendered and the long tough protein strands have started to break down, and we get tender or even shredded meat.
Underdone BBQ is like Overcooked Steak: Dry and Tough
Overcooked BBQ is like cat food: stringy and mushy and falls apart.
But why?
When our cooked-to-130F Steak tastes moist, it's because of juices / water Moisture.
When our cooked-to-205F BBQ tastes moist, it's NOT water, it's fat. It's rendered fat.
We get a lot of questions about Chuck Roasts. People cook their chuck
roasts "like a Brisket" up to 203F, but it is still "dry and tough."
Even though it hit 203F, it is still under-cooked.
This is because of TIME and Temperature. Basically every minute spent over 130F, the fat is rendering in some capacity. Briskets are comparably easy to understand because to get them up to 203F, they've spent 10+ hours rendering. They've got a huge thermal mass that takes a while to come up to temp and have a nice gradual cook. A Chuck Roast is as tough as Brisket, it comes from the next muscle group. But they're cut much smaller, and so shoot up to 203F in only about 4 hours, and don't have as much time to render. So we keep cooking it. But we need to make sure we don't burn the exterior or cook it so hot ALL the fat renders and it ""dries out."" So, we can keep it in a broth bath for more gentle cooking. We can spritz it. We can sous vide it. We can ""rest"" it (carry-over cook) at 160F+. But it needs more time to break down.
