Your Cob Barrel is a relatively simple unit. It doesn't need a chimney, as it’s barrel chamber has 4 vents that create airflow directly across the coals. There is no 'offset' for the fuel, which means this little beauty can grill directly like a standard BBQ, or indirectly like a smoker.
How Vents Work
Think of the bottom vents as the air intake and the top vent as the exhaust, that also draws the air through the chamber. If you want your fire hotter – open up the vents. Always have the vents in a fully open position when starting your fire.
The illustrations above show two different ways to use the vents to control the air-flow and therefore temperature in your Cob.
Pic A. Illustrates the Indirect or Low and Slow method of cooking. The coals are away from the meat and the two opposing vents are fully open. Cold air is naturally drawn in through the bottom vent, then it is drawn through the chamber, circulating as it is heated by the fuel. It then vents out again at the top open vent, as hot air rises.
Pic B. Illustrates the direct cooking method. This is where the Cob behaves like a normal BBQ and the meat cooks over the heat directly. All four vents are partially closed; the cold air comes in the bottom and circulates around the barrel and is vented out the top on both sides. You can also cook with the lid fully open.
Controlling Temperature and Air Flow
To increase the temperature inside the barrel, open up two opposing vents, the more air going through the unit means more air going past the coals, and they heat up. This increases the speed the top vent pulls air through at, thus increasing the temperature and so on.
If you want to regulate the temperature, start by half closing the aperture of the bottom vent. Leave the top one open for 5 minutes and monitor the temperature. Then slowly start closing the top vent, bit by bit and monitor the results. You'll soon get a feel for your Cob and know how to adjust your temperatures accurately.
Remember that opening your Cob and adding meat will adjust the temperature initially, so adjust as you go.