The rules for grilling vegetables are pretty much the same as those for grilling meat or seafood: Keep it hot. Keep it clean. Keep it lubricated. In other words, you want to start with a hot clean grate that you oil right before the food goes on.
Heat your grill grate well, then scrub it with a stiff wire brush or scrape it clean with a wooden scraper.
To oil it, fold or roll a paper towel into a tight pad, then clasp it in long-handled tongs. Dip it into a small bowl of vegetable or olive oil, and rub it across the grate in the direction of the bars. In addition to oiling the grate, this has the added advantage of giving the grate one last clean—and catching any stray brush bristles. Re-oil the grate as cooked vegetables come off and new ones go on. Note: When grilling smooth-skinned vegetables, like whole eggplants and bell peppers, it is not necessary to oil the grate. But it doesn’t hurt—and it helps put a better nonstick finish on your grate if you do.
And when you’re done, brush and oil the grill grate one final time so your grill is clean and lubricated for your next grill session.
When grilling multiple vegetables (or smaller vegetables or bread or tofu slices), arrange them in orderly sequential rows, starting in the back, working your way forward. That way, you know where you started and which piece to turn when.
Always leave at least 25 percent of your grill grate food-free—and preferably fire-free beneath it. This is your safety zone, where you can move the vegetables if they start to burn or if the fire gets too hot.
So how do you know when a particular vegetable is done? Unlike with grilling and smoking meat, I rely less on internal temperature and more on look and feel to gauge doneness.
- For small skinny veggies, like scallions and asparagus, when the outside is blistered and darkened, the vegetable is cooked. Ditto for sliced vegetables, like eggplant or zucchini.
- For small round or pod vegetables, like tomatoes or okra, use the pinch test: Pinch it between your thumb and forefinger. When squeezably soft, it’s cooked.
- For larger vegetables, like squash or potatoes, use the skewer test: When you can easily pierce the vegetable with a slender metal skewer or cake tester, it’s cooked.
Grilling Vegetables Versus Grilling Meat
Many vegetables are grilled the same way as animal proteins. You direct grill a portobello mushroom cap, for example, just as you would a steak. (In fact, grilled portobellos are often served as “steaks.”) Indirect grilling a whole squash or head of cauliflower is no different than indirect grilling a chicken.
But there are a few key differences between meat and vegetables, first and foremost of which concerns fat.
All animal proteins contain fat. Some, like pork shoulders or ribs, contain a lot of fat, which helps keep them succulent during grilling or smoking. Vegetables contain no intrinsic fat, so you have to add fat to keep them moist. That fat can take the form of olive oil in a marinade, butter in a baste, or a strip of bacon or pancetta wrapped around a jalapeño pepper, an ear of corn, or a wedge of acorn squash.
All animal proteins contain water (roughly 75 percent per pound). Vegetables are mostly water, too, but the water content varies. On the high end, you have tomatoes and peppers (roughly 95 percent). Dense root vegetables, like parsnips and rutabagas, contain around 80 percent. High-moisture vegetables lend themselves to quick, high-heat direct grilling, whereas lower-moisture vegetables require the gentle prolonged heat of indirect grilling. The same is true for dense vegetables, like beets and kabocha squash.
Vegetables absorb wood smoke very differently than meats. Smoke penetrates the moist, porous surface of meat easily, which is why Texas brisket and Kansas City-style ribs acquire such a delectable flavor (and smoke ring) with prolonged smoking. This is not the case with hard vegetables, like turnips and beets. The smoke tends to stay on the surface, which is why many smoked vegetables wind up smelling like ashtrays rather than barbecue. Moisture-rich vegetables, like tomatoes and onions, do best with straight smoking. Denser, drier veggies, such as turnips and rutabagas, should be blanched or boiled before smoking.
Boiling Is Not a Dirty Word
One of the canons of carnivorous barbecue is that you should never, ever boil ribs (or other meats, like chicken or brisket). Yet many vegetables contain a hard, fibrous, insoluble substance called cellulose, which makes it difficult to achieve tenderness and moistness solely by direct or indirect grilling. For this reason, I sometimes call for blanching (briefly immersing a vegetable in boiling water) or parboiling (partially cooking a vegetable in boiling water) prior to cooking. This is especially true for hard or dense vegetables, such as artichokes or cauliflower.
Note: The water should be well salted and rapidly boiling for green vegetables—this keeps them bright green. When cooking root vegetables such as potatoes and rutabagas, start them in cold water, then gradually bring them to a boil. This allows the starches to expand slowly, minimizing a mealy texture.
Crunch and Crust
Grilling is my favorite cooking method for vegetables (surprise!), searing (even charring) the exterior, caramelizing the natural plant sugars (which gives grilled vegetables a supernatural sweetness), and gently infusing the vegetables with the flavor of wood smoke. The one thing grilling can’t do is give you a crisp crust (the sort that results from sautéing eggplant slices dredged in flour, for example, or frying sweet potatoes in tempura batter). But there is a way to give grilled vegetables that crunch, and that’s by topping them with toasted or sautéed breadcrumbs or nuts, or crumbled slices of grilled bread.
Finally, there’s the question of size. Most meats, with the exception of chicken wings and shrimp, are at least single-portion serving size. Many vegetables come in bite-size or smaller pieces: The short list includes green beans, asparagus stalks, edamame, and Brussels sprouts. So, you need to group small vegetables together for grilling. One method is to thread them onto skewers to make kebabs or rafts. Another is to grill them on a vegetable grid or in a wire-mesh grill basket.
So, now you know the basics and fine points of grilling vegetables. It’s time to fire up your grill!
Excerpted with permission from “How to Grill Vegetables” by Steven Raichlen, photographs by Steven Randazzo. Workman Publishing copyright 2021.