The Art of the Wood Cookstove

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• Inefficient burning. In a wood cookstove, flames rise directly to the underside of the cooking surface, which might be an advantage for quick heating, but also results in incomplete and sooty combustion by quenching the flames before all the smoke has burned. Another problem is that the fire rests on a grate in most cookstoves and receives its combustion air from below. Wood burns best on a solid surface with the combustion air reaching the fire at or above coal-bed level, and, in fact, no stove of “underfire air” design has ever passed the EPA smoke-emission limits.

Cookstove users can partially overcome this problem by controlling the amount of wood burned at one time, which is more effective than turning the air control down. Tettemer recommends adding at least three small sticks per load and placing them in a crisscross pattern so they flame brightly. He admits that the overnight fire in his cookstove is “an intentional smolder” that he knows will deposit a thin layer of creosote — dark, flammable tar — in the oven passages. He makes up for this by cleaning the oven passages monthly.

• Smoke leakage into the living space is another drawback of the traditional design. The cook surface is porous because the top plate holds four or six round cook plates. The resulting gaps create ready sites for smoke leakage under some conditions. In baking mode with the bypass damper closed, the exhaust gases are forced to go down one side and then under the oven. Hot air rises, and hot exhaust gases are no different. So, when chimney draft declines because of low firing and a cold chimney, smoke can find paths through the gaps in the cooktop instead of being drawn down around the oven. This slow leakage of smoke into the house is Tettemer’s biggest complaint about his cookstove. He avoids the problem by leaving the bypass damper open a crack to ensure that even when draft is low, the smoke will go up the chimney instead of into the room.

Tips for new Users

King says that one of the best things new cookstove owners can do is to invest some time in learning how to use the oven bypass damper. “It took us a long time to learn how to use it,” he says. “Make sure you know the controls.”

When open, the bypass damper allows the exhaust to pass directly from the firebox into the flue when starting and loading the stove. When closed, it forces the hot exhaust across the top of the oven, down the far side and then under the oven into the flue. Smoke-free operation and successful baking both depend on the correct use of the damper.

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