Where to put the beef flank fat in the smoker

Beef skirt steak has two sides: one with a thick layer of fat and the other with some fine marbling, but mostly bare meat. Some people trim off all the fat, while others prefer to leave a thin layer of about 1/4 to 1/8 inch.

The idea that fat melts into the meat to keep it juicy is a myth. The meat doesn't absorb the fat; it drips down into the drip tray, carrying the seasoning with it. Furthermore, with the fat facing upwards, the crust doesn't form evenly.

With the fat side down, the layer protects the meat from the intense heat, and as the smoke drips onto the coals, it adds flavor. Since the Maillard reaction requires a dry surface, the crust forms evenly when the fat doesn't cover the meat, resulting in that dark, uniform, licorice-like crust.

The heat source is key. In most smokers, the heat comes from below, as in a Weber Smokey Mountain Bullet charcoal smoker, and the fat should face down. In horizontal, indirect-draft smokers, the heat comes from above, so the fat should face up because it acts as an insulator. In either case, if the fat-free side dries out, it can be wrapped in aluminum foil or butcher paper halfway through cooking.

Experts disagree. Malcolm Reed of How To BBQ Right cooks his briskets fat-side up, as does Aaron Franklin, though both use smokers with a top heat source, which explains their choice. Meathead Goldwyn of AmazingRibs.com saves the fat cap and places it over the fire to drip, because the fat that falls onto the coals comes back as flavorful droplets mixed with the smoke.

Removing the fat cap is a matter of personal preference. In a high-quality cut, such as Wagyu, it can be removed entirely, although it's advisable to leave at least a quarter of an inch, as the fat contributes to the flavor.