When it comes to grilling tips, I always wonder: Should I lower the lid on the grill, or not? It seems like such a simple question. But, unlike the perfect method for boiling an egg or the ideal strategy for cooking a steak indoors, the grill-lid conundrum is one that neither your grandmother nor the vast expanses of Google can ever seem to answer. The result? Every summer, we all stand in front of the grill in a state of wretched uncertainty, not sure which path leads to perfectly cooked food.
Luckily, in his book Meathead: The Science of Great Barbecue and Grilling, Meathead Goldwyn offers up a simple rule of thumb.
Check the thickness of the food
It's simple. If the food you’re grilling is ¾ inch thick or less, don’t put the lid down. If it’s over ¾ inch—you guessed it—cover that sucker up.
Closed lid means convection
When we’re grilling, we all aim for food with a crusty, slightly charred exterior and a moist, tender interior. We want that result whether we’re cooking a thin flank steak, or a thick slab of ribeye. We want it when we grill wispy asparagus, and also when we grill hearty potatoes. But, though the destination is the same, the journey is different for thin foods than thick ones.
When you close the lid to the grill, you’re creating a convection. That is, the hot air coming from the heat source (gas or charcoal), trapped by the lid and unable to escape, moves around in the chamber you’ve created. Thus, the closed lid helps the interior of the meat cook through, much like an oven does.
Open lid means searing
With thin foods, if you close the lid—allowing the convection heat to come at the food from above and below and all around—the center of the food will cook through before the outside is browned and caramelized. When you cook with the grill open, you’ll more effectively get a crispy, perfect-Maillard-reaction caramelization on the outside of the meat without overcooking the center.
Foods thicker than ¾ of an inch, though, literally have more middle to cook. So, they can hold up to the heat chamber the lid creates, and in fact, the lid will help thicker cuts of meat or vegetables cook more evenly. You’ll avoid an undercooked center with an overly browned, crusty exterior.
Are there any exceptions to the rule?
Even though she didn’t teach you the rule about your grill lid, your grandmother probably taught you that the rules of life are rarely black and white. Sometimes you’ll want to employ both techniques to get the perfect balance of caramelized crust and perfectly cooked middle, especially on those cuts that are towing the ¾-inch line. Here you can employ a combination approach, says Meathead—just another one of his genius grilling tips. You’ll first sear the meat directly over the flame and get a good char going. Then, you’ll move it away from the direct heat source to the side with indirect heat (you did set up a two-zone grill, didn't you?), turn down the lid, and let the center cook through. Or do the opposite: Cook the meat with the lid down until the center is perfectly cooked, then open the lid and move the meat over direct heat (BBQ gurus are big fans of this "reverse sear" strategy).
