If you've never cooked food right in hot coals before, try it. You get intense smoky flavors and a great browned crust. Plus, it makes you look like a Master of Fire. Porous foods like fish absorb more woodsmoke, while dense foods like beef steak develop a thick crust. Here's what we found out in our latest experiment cooking in the coals.
A: Last week I made tuna steaks in the coals. But it was so different than the usual rib-eyes and strip steaks we usually do in coals.
D: How so?
A: Well, we’ve been cooking steaks right in the coals for years now, but last week with the tuna steaks, my thinking about this cool grilling technique did a complete 360.
D: What happened? You mean it’s not a cool technique?
A: No, no, it’s cool. It’s even cooler than I thought! That’s just it. I was afraid I was going to overcook the fish because my thinking about cooking anything in the coals is that the fire is really, really hot. I wanted some way of taming that heat. Most of the time when you’re grilling, you can turn down the heat or raise the food away from the heat. But when you’re cooking in the coals, you can’t do that. The food is right down there in the fire. It’s blazing hot, right?
D: Well, maybe.
A: Exactly. What I found is that it’s not that hot. Right there in the fire! Even though the tuna sizzled like spit on a griddle when it hit the hot log, the surface of the fish barely browned.
D: A-ha. That’s because you put the fish on the flat side of a burning log, which isn’t as hot as you’d think. It’s cooking between the coals that’s really hot... Remember when we did that podcast for Mastering the Grill? We were trying to get those strip steaks in the coals to cook, but they were taking forever? It’s because we put them on the flat side of the logs. The logs had burned down pretty well, but they were still whole. We turned a couple logs over with the burning side up and put the steaks on the flat side, thinking the logs would keep the steaks nice and stable and cook them evenly. But it took a long time for them to cook through. That’s when I realized that there was barely any oxygen between the steaks and the wood. So little that the heat was really low. It became crystal clear when I noticed the piece of steak hanging over the edge of the log. That piece charred and cooked through quickly but the piece sitting right on the wood didn’t.
A: That’s interesting because that’s how I ended up doing the tuna steaks to keep them from overcooking. I put them on the flat side of a burning log. For something like tuna, it worked because it kept the tuna rare—even raw—inside, which is perfect. And I got much more wood flavor that way, probably because the tuna is more porous.
D: Bingo. The tuna is more porous, so it absorbs more smoke aromas. Same thing with vegetables. They absorb a lot more smoke flavor when cooked in the coals than something dense like steak will absorb. I’ve done beef steaks both on the flat side of burning logs and on burned-down embers. The beef doesn’t get intensely smoky like the tuna would because the beef is so much more dense.
A: It’s a really cool technique, but what surprises me about cooking in the coals is that what you get is totally different than what you’d expect. I mean, you’re putting food right in the fire... you feel like you’re going to burn the crap out of it! But the food doesn’t burn. That’s the surprising part.
D: But it makes sense when you think about it. Because you don’t actually put the food right into the fire. The fire doesn’t exist where the fuel is. The fire exists where the fuel and oxygen combine. And that’s right above the coals not right in them. That’s why cooking on a grill grate, above the fuel, will give foods a great charred surface, but cooking right on the flat side of a burning log gives you almost no charring at all. There’s no fire there.
A: So how do you get a lot of charring when cooking in the coals? Like if you want a good crust on a steak? We usually advise people to rake their coals into a pretty flat bed. But maybe we’ve been wrong. Maybe we should be telling people to rake the coals into a lumpy bed.
D: I guess that would be more accurate. A slightly lumpy coal bed would give you more pockets of air between the coals, which means more heat and better charring. But the reason to rake the coals is to create a relatively stable surface to hold the food. I’ve had the best results when’s there a mix—a mix of coals burned down to nuggets about one inch square plus some logs that aren’t quite yet burned down to nuggets. That’s if you want charring, like with a steak. But for the tuna you don’t want that much charring.
A: Right. The tuna worked really well because charring means heat. And you don’t want a lot of heat for the tuna. You want the middle to be raw, bare flesh. You want it to still be cool inside. With the tuna on a flat burning log, it got only a thin crust and almost no char. But it got intensely smoky, giving you this mind-blowing contrast of untouched virgin fish flesh and wood-drenched meat surrounding it.
D: Yum! So either way, the big advantage of cooking in coals is flavor. With dense foods like steaks, you get intense surface browning, a thick crust, and deep roasted flavors. With porous foods like fish or eggplant, you may not get as much charring, but you get great smoke flavors.
Bonus audio: What is Fire?
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Raw Charred Tuna with Green Tea Ponzu Sauce
Makes 4 servings
2 tablespoons jarred pickled ginger (for sushi), finely chopped
2 thin scallions, root ends and dry ends trimmed, finely chopped
1 medium garlic clove, minced
2-inch thick tuna steak, about 1 3/4 pounds total
1 tablespoon dark sesame oil
1 tablespoon Mustard Wasabi Rub
1 tablespoon sesame seeds
1 1/4 cups Green Tea Ponzu Sauce
Combine the pickled ginger, scallion and garlic. Insert a thin-blade knife 3 to 4 times into the narrow sides of the tuna steaks creating punctures going directly toward the center of the tuna steaks. Stuff the holes with the ginger mixture. Coat the tuna steaks all over with sesame oil.
Combine the wasabi mustard rub and sesame seeds on a sheet of foil or plastic wrap and coat the narrow sides of the tuna steaks (not the broad flat sides) with the mixture.
If using charcoal even the fire bed as much as possible. If using wood turn the logs split-side up. Blow off excess ash with a leaf blower.
Put the steaks directly on the hot coals and grill until bottom side is crusty, about 1 1/2 minutes. Turn with a long-handled tongs, picking off any coals clinging to the surface and grill 1 1/2 minutes on the other side. Remove to a cutting board.
Slice against the grain into 1/4- to 1/2-inch thick slices and serve with the ponzu sauce
Mustard Wasabi Rub
Makes 3/4 cup
2 tablespoons wasabi powder
2 tablespoons sesame seeds
2 tablespoons kosher salt
2 tablespoons sugar
2 teaspoons garlic powder
2 teaspoons ginger powder
1/2 teaspoon cayenne pepper
1/2 teaspoon ground black pepper
Mix everything together; store in tightly closed container for up to 1 month.
Green Tea Ponzu Sauce
Makes about 1 1/4 cup
2 teaspoons kosher salt
2 teaspoons light soy sauce
2 teaspoons rice vinegar
1/4 cup mirin
Mix everything together; store in tightly closed container in the refrigerator for up to 1 week.