Smoking food is one of the oldest cooking methods. Using slow, steady smoke and heat to cook meat adds deep, complicated flavor to all sorts of meat and cheeses and is essential to creating certain dishes. Many smokers are poorly insulated and lose heat during the smoking process. For this reason, it is important to insulate most smokers. There are a number of different techniques for improving a smoker's insulation, and with the right equipment you can effectively insulate a smoker.
Wrap the smoker in an insulation blanket. These blankets generally have an interior aluminum layer and an exterior fabric layer. Wrap the smoker so the aluminum layer is in contact with the surface of the smoker, wrapping the blanket around the smoker and over itself so the blanket is held in place by its own weight. Do not wrap the blanket around the firebox.
Wrap the smoker in a welding blanket. These blankets are designed to protect from heat and sparks during the welding process, so they can stand up to a great deal of heat. They vary in thickness and materials and should be wrapped around the smoker but not the firebox. Wrap the blanket around the smoker as many times as possible and over itself so the blanket is held in place by its own weight.
Cover the smoker with an insulating jacket. Many smoker and smoker supply companies manufacture insulating jackets for smokers. Generally these jackets are made of aluminum-covered fabric and are made in the precise shape of the smoker to slide over the smoker.
Check to make sure there is no active fuel burning in the firebox. Measure the interior of the firebox with a tape measure and mark these measurements on a piece of cement board. Score the cut marks on both sides of the cement board with a utility knife. Hold the cement board piece you wish to remove over the edge of a flat surface and press down to break it off. Place these cement board pieces against the interior walls of the firebox. The cement board will help insulate the firebox and prevent heat loss.