I sometimes smoke my food, especially when I’m grilling. Often when meats and vegetables are smoked, the smoke from burning wood deposits a layer of tarry molecules on the seasoned steak, protecting it from bacteria while adding a complex dimension of flavor. Uncooked meats are usually treated with a combination of smoke and heat, but some cooked foods, such as seafood, are cold smoked. The food is kept in a separate chamber so that it gets the smoke from the burning wood, but not the heat.
At home, I use dry sawdust instead of wood chips—a trick I picked up at the Culinary Institute of America at Greystone, in California—because sawdust burns faster. Some cooks prefer to soak the wood chips in water before adding them to the grill, so the wood won’t burn as fast. I find this works best when food needs to be smoked for several hours.