In the first installment of our BBQ Pit Primer, we looked at open and closed barbecue pits, in which the meat is cooked over direct heat. We get a little smokier this week as we round out the topic with a look at offset smokers as well as the latest generation of automatic barbecue cookers.
When it comes to offset pits, it's all about smoke and indirect heat. Split logs are burned in a fire box on one side of the big cooking chamber, and a chimney on the far side creates a draft that draws the heat and the smoke from the burning logs directly over the cooking meat. Reverse-flow smokers, like those made by Lang BBQ Smokers of Nahunta, Georgia, take things a step further. The chimney is on the same side of the pit as the firebox, and the smoke flows to the far side of the pit along the bottom and is drawn back to the front and out the chimney.
Many of Texas’s most acclaimed brisket masters, like Aaron Franklin of Franklin Barbecue and John Lewis of La Barbecue, make their own offset smokers, fabricating them from old propane tanks and adding tall smokestacks and dampers to ensure a strong airflow. If you want to built your own smoker, Franklin offers detailed instructions in his recent book Franklin Barbecue: A Meat Smoking Manifesto (welding skills required).
Indirect heat and smoke are two key differences between offset pits and the older style of open pits. In an offset cooker, the heat source is set off from the cooking chamber (hence the name), so there's no direct heat radiating onto the meat. Since split logs are burned directly in the firebox of an offset pit, the chamber is filled with a lot more smoke than in the open varieties, and that results in barbecue that's more heavily smoked than that cooked on an ember-fired open pit. Offset pits truly are barbecue "smokers."
Electric or Gas Cookers
Cooking on old fashioned barbecue pits requires a lot of labor: hauling cords of expensive wood, staying up all night shoveling coals into pits, turning large cuts of meat, and watching for grease fires. Over the years, all sorts of inventive minds have tried to lessen the burden and let barbecue cooks get a little sleep at night. Various types of automatic cookers have been used since the 1950s, and they have come a long way in recent years.
The models that first gained widespread adoption in restaurants in the 1970s were little more than electric- or gas-fired ovens—stainless steel cases with racks to hold the meat and a thermostat to control the heat so the cook could “set it and forget it.” A handful of wood chips smoldering on a metal plate or in a small firebox might add a touch of smoke, but often the meat emerged with a hint of oak or hickory. Some of those old-style pits are still around, but far more common are the so-called gas-assist cookers made by firms like Southern Pride and Old Hickory. They're downright sophisticated devices: gleaming stainless steel bodies, thermostatic controls, motor-driven rotisseries.
Though gas burners are the primary heat source, these new pits burn real wood inside—whole fireplace-sized logs, in fact. When you see one in action, you realize it has a sort of big gas-powered flamethrower that sends a stream of fire over the logs. That burner brings the oven up to whatever temperature is set on the thermostat then cycles up and down to keep the heat constant, while the burning logs (usually just 2 or 3 per cooking session) provide plenty of real oak or hickory smoke.
It may seem counterintuitive, but modern gas-fired cookers often create a much more heavily-smoked end product than an all-wood open pit, since the smoke from the burning logs is held inside the oven and bathed steadily over the meat with convection fans. Southern Pride cookers even boast a trademarked "Subthermic flue system" to ensure "maximum smoke intensity."
High-Tech Wood Burners
Electric- and gas-fired cookers still create plenty of debate among barbecue fans. The purists say it's not real barbecue if it's not cooked on all wood, while the pragmatists point to the burning logs inside gas-assist pits and the many business advantages that consistent thermostat-regulated heat brings. Some pit designs try to combine the best of both worlds, providing 100%-wood burning pits with many of the same automated control features of the gas-assist versions.
One of the most popular brands in the Lone Star State (and, increasingly, in the country at large) is the Oyler rotisserie smoker, which is made by J&R Manufacturing of Mesquite, Texas. The Oyler is fired solely by burning hardwood, but it has a Ferris wheel-like rotisserie of motorized racks that keeps the meat moving as it cooks. An automated control system regulates the amount of air delivered to the burning wood, allowing the barbecue to cook unattended for 12 hours or more while controlling smoke and humidity, too.
As the barbecue restaurant industry evolves, innovative cooks will continue their efforts to improve on the original ember-fired open pits and closed brick pits, seeking that magical blend of heat, smoke and time that's essential for great barbecue. We'll leave it to partisans to debate how well each succeeds, but this much is clear: of the many elements that determine the final flavor of the barbecue we eat, one of the most important starts all the way at the beginning with the design of the pit on which it is cooked.