This is the method most home cooks will actually use. A 22-inch Weber kettle or comparable barrel grill handles tri tip as well as any dedicated Santa Maria rig. The technique is what matters, not the equipment. Set up a two-zone fire, sear over direct heat, finish over indirect, pull at temp. That's the whole method.
Choosing Charcoal
Lump charcoal is the closest substitute for traditional red oak coals. It burns hotter, cleaner, and gives you real hardwood flavor. Jealous Devil and Fogo are widely available and reliable. Briquettes burn longer and more evenly, which makes them better for smoked cooks at 225°F. Kingsford Original and B&B are solid picks. Avoid match-light or any briquette with lighter fluid baked in; the petroleum aftertaste lingers in the meat.
Two-Zone Fire
Light a full chimney of charcoal (about 100 briquettes or 5 cups of lump). When the top coals are ashed over and glowing, dump them on one half of the grill to create a hot zone. Leave the other half empty for indirect heat. This is the single most important setup move for tri tip: it lets you sear on one side and finish on the other without fighting the fire.
Add 2 to 3 chunks of red oak, post oak, or cherry directly on top of the coals for smoke flavor. Avoid mesquite as the primary wood for tri tip; it burns hot and overwhelms the lean cut.
Vent Management
The bottom vent controls airflow and therefore heat. The top vent should almost always stay wide open and directly above the meat to pull smoke across the cook. For direct searing, open the bottom vent fully. For the indirect finish, close the bottom vent to about ¼ open to hold 325–400°F. If you overshoot, close the lid vent halfway for 60 seconds to drop temp, then reopen.
Grate Prep and Cook
Preheat the grate with the lid on for 5 minutes before the tri tip goes on. A hot grate sears the meat on contact; a cold grate steams it. Brush the grate clean and oil it lightly with a paper towel soaked in high-smoke-point oil held with tongs.
Season the tri tip with salt, pepper, and garlic powder. Let it sit at room temperature for 30 minutes while the coals come to ashed-over white. Place the roast fat cap up over the hot zone. Sear 5 to 7 minutes per side with the lid off to build a crust. Then slide it to the cool zone, close the lid, and hold 350 to 400°F at the lid thermometer until the internal hits 128 to 130°F, usually 20 to 30 more minutes for a 2-pound roast. Pull, rest 10 minutes uncovered, slice against the grain.
When to Reverse the Order
For thicker roasts (2½ inches or more at the heel), flip the sequence: start over the cool zone until 110°F internal, then sear over the hot zone to finish. That's effectively a reverse sear on a charcoal grill: edge-to-edge pink with a hard crust, no gray band.