Consensus versus science
In general you will find that knowledgeable people say you must let meat rest right off the grill or right out of the oven. First off, they’re not the boss, don’t tell us what to do. More importantly though, is the why behind resting accurate? Does it make a difference or are we just perpetuating another kitchen myth? The answer to both is; possibly.
Taking the meat from the heat source still leaves energy in the meat which will cause some degree of carry-over cooking. That means at the end of the rest the meat will be more cooked than when the rest began. Heat also creates evaporation. During a rest period meats have been found to evaporate by weight about half the amount of juice that will be on the plate when cut. And they are cooling down, so you could ultimately serve an almost cold steak if you wait too long.
Conversely, as meat cools it begins to become firmer as it restructures, this firmness will hold more juice. This especially becomes noticeable with thick cuts and roasts. And that is a distinction to note.
Clarification
Delving deeper into the topic and exploring the science you will see two different standards. Steaks and chops, typically sliced across the grain, and smaller intact cuts like chicken pieces, will gain very little benefit from resting after the cooking process.
Roasts and whole fowl or such will benefit more from the resting process. In this case the carryover effect works to your benefit. For larger cuts it is all about getting the heat to penetrate to the point of cooking to your chosen doneness throughout. Removing it from the heat will give you carryover, sometimes a significant amount. So a 15 minute rest for a roast can easily see a core climb of 5°F or more taking you from medium rare to medium for example in the case of steak. In the case of a turkey, for example, you can pull it 5-10°F below your target core temp and after a rest it will be at your goal.
We also discourage a foil wrap. This only creates more carryover cooking, making things overdone if not careful. It also makes the meat sweat, softening up the crust or crispy skin you just sent time creating. With a large roast, feel free to tent it with foil to keep the upper portion from cooling too quickly, but do not enclose it in foil.
Reality bites
Let’s talk real life. How often does a steak go from the flame to table to cut up instantaneously? Unless you are the super cook with lots of assistance the answer is almost never. Inevitably you have side dishes, napkins to place in your lap, pouring the wine, maybe even a toast…you get the idea. The point being that there is a natural amount of a rest period just in the nature of putting together the meal.
But you know what? Cutting into a properly cooked steak that is still sizzling from the skillet or grill is absolutely amazing. We would challenge you to notice any difference in juice lost compared to letting it rest. The other aspect of reality is that we do not typically inhale the meat immediately. Enjoying the other dishes, chatting with fellow diners, sipping some beverage; these all slow down the eating process so that some rest, again, occurs naturally in the dining process. At a minimum you have to cut the bite size pieces that you like, allowing the bulk of the steak to rest in the process.
In conclusion…
There’s a negligible difference between a steak that rested and one that did not, plus the natural process of dining allows for some rest anyway.
Larger cuts, and intact fowl, will benefit from some resting to equalize temperature.
Lastly; bread, That’s right, no matter what you decide to do, there will likely be some juice on the plate. If dragging your next bite through that juice doesn’t soak it up, drag a nice slice of bread to do the cleanup. Eat that too.