Because the heat of a charcoal or even gas grill can be so intense, it can cause foods to overcook quickly and dry out, various techniques have evolved (such as indirect grilling and building a two-zone fire) to try to combat some of these unwanted effects.
One such technique is grilling on a wood plank. If you're familiar with this at all, you've probably heard of it as a technique for cooking fish, especially salmon. A wood plank is wonderful for fish, but you can actually use the technique on other ingredients.
How Does It Work?
The way wood plank grilling works is simple. In a nutshell, the plank goes on the grill, then the food goes on the plank. The food cooks via indirect heat, since the plank protects the food from the fire. You don't have to flip the food when you're cooking it on a plank. This makes it ideal for cooking delicate ingredients like fish that can fall apart when you try to turn them. The underside of the plank will also start to smolder after a while, which will impart a smoky flavor to whatever you're cooking.
The Different Woods Used for Plank Grilling
The most common type of grilling plank is cedar. Alder and hickory are also fairly easy to find. Cherry, maple, and red oak are also good choices and sometimes you can find a variety pack of planks in various flavors.
The key, however, is to make sure you are buying grilling planks and not just pieces of plywood. Construction wood is treated will all kinds of substances that make it good for building, but when burned, those substances will release unwanted flavors and possibly toxins. Even though you can find untreated wood at the hardware store, but to be certain, make sure yours is specifically made for grilling.
The thicker the plank, the better, but try to use ones that are at least half an inch thick. Also, make sure the plank is large enough so that whatever food you're cooking will fit with at least an inch of exposed board all around.
Soak the Plank Before Grilling
As we mentioned, part of the objective with grilling on a plank is to impart wood smoke flavor to the food through the slow smoldering of the plank. But slow smoldering is far different from full combustion. In other words, you don't want the plank to be engulfed in flame. To prevent that from happening, it's crucial to soak the plank before using it.
This is done simply by submerging it in your kitchen sink or a large container while keeping it weighted down so that it stays submerged. Your grill planks probably come with instructions, so follow them. But in general, you'll want to soak the fully-submerged plank for an hour. After this time, take it out of the water, let it drain, and pat it try with a paper towel. The plank should be damp, but not dripping wet.
How to Grill Fish on Wood Planks
Grilling fish on a plank is super straightforward. Start by brushing the top of the plank (which you've previously soaked and patted dry) with oil. Don't oil the opposite side though (i.e. the side that will be in contact with the grill). Next place your fish skin-side-down on the plank, then brush the fish with oil, and sprinkle it with seasonings, lemon juice, herbs, and so on.
Heat your grill to medium-high heat and place the plank with the fish on it directly on the center of the grill. Cooking time will depend on thickness of the fish and other variables, but a two pound salmon fillet will take about 15 minutes.
You can also grill a whole fish such as trout on a plank.
Grilling Other Foods on a Plank
This same basic technique can be used to cook foods other than fish. Foods like chicken, pork, and beef can also be grilled on a plank. Note that when grilling a steak, the goal is to get the grill as hot as possible and get the steak on and off as quickly as possible, which is directly counter to the effect plank grilling produces.
On the other hand, you can sear your steak over a very hot skillet and then finish the cooking on a plank. Some cooks have even experimented with blackening the plank over a hot grill, then turning it over and placing their meat or poultry on the blackened side before transferring the plank back to the grill to cook, with the charred surface of the wood imparting a more intense wood flavor.
Finally, you can reuse your planks as long as they don't crumble apart from the charring. Just rinse it off with plain water (no soap) and let it dry. And keep in mind that they will take on the flavors of what you've cooked on it previously, so for instance, you might want to stick with salmon once you've used one for salmon.