Have you ever been to a great barbecue restaurant and just stood outside and inhaled that wonderful smoke billowing from a wood fired, brick pit? There is just something special about how barbecue smells as it slow cooks for hours upon hours. Let’s get to work now on trying to duplicate that same aroma in your own smoker.
The best woods to use as a fuel source are hardwood's. This includes such woods as hickory, oak and pecan. Hickory, oak, and pecan are also excellent woods for their smoke flavour. Fruit woods could be used as a fuel source, but their best use would be in combination with either a hardwood or charcoal as the main fuel source. Fruit woods would include apple, cherry, and peach.
Wood can come in several forms. Logs, split logs, wood chunks, chips, and pellets. As a fuel source, wood in the form of logs or split logs is the best choice for providing the most BTUs. Wood chunks can be used to provide heat, but really are better suited for adding smoke flavour. Wood chips provide little heat but a lot of smoke. Wood pellets are a compressed wood product. Some smokers like GMG and Traeger use pellets as the heat source and smoke flavour.
Most barbecue woods are cut from hardwood's, fruit woods, and nut woods, but never pine and softwoods that have a lot of turpenes and sap. Used in what are affectionately known as stick burners that have a large firebox at one end to burn the logs in. Some cooks throw whole logs into their pits, but you must have the right pit and skill set to pull this off. Done improperly this can easily ruin your meat.
Wood chunks from golf ball to fist size are fairly easy to find in hardware stores. Chunks burn more slowly that chips, and often a chunk or two about the size of an egg weighing 2 to 4 ounces (0.15 kg) is all that is necessary for a load of food. Because they are slow, steady sources of smoke, they are in many ways, the most desirable. When you use chunks, you can add one or two at the start of the cooking cycle and you don't need to keep opening the unit and mess with the equilibrium in the cooking chamber's atmosphere.
About the size of coins, chips are also common and easy to find. They burn quickly and you may find that you need to add them more than once during the cooking cycle. Chips are fine for short duration cooking, but for long duration cooking, chunks are better.
Pellets are made by compressing wet sawdust and forming them into long strips. They are then broken into small pieces of about 1/2" long. Food grade pellets contain no binders, glue or adhesives, so that, when they get wet, they revert to sawdust immediately. Some smokers use pellets as the main fuel, for both flavour and heat, which means that pellet cookers do very well in competitions. Because they can be fed into the fire in a very controlled manner, pellet cookers are usually regulated with a thermostat, making them very easy to control. They burn very hot and clean.
Sawdust can also be used for flavour, but it burns quickly and is rarely used. It can be used effectively on thin, fast cooking foods like fish fillets or minute steaks.
TIP: If you are just learning the art of smoking your meat, start off using a small amount of wood to see how you like the flavour. You can then add more wood to increase the smoky BBQ flavour. Don't overuse it. It is possible to get too much BBQ smoke flavour over long cooking periods, this could make your meat bitter. This is particularly true with the heavier wood flavours like hickory and oak. Mesquite and the fruit woods just don't seem to do this to your meat because of their lighter smoke flavour. The rule of thumb is 1 to 2 cups or 1 to 2 handfuls.
TIP: Meat that has been smoked tastes even better on the second day. The smoke flavour seems to get better with time. So, your leftovers just taste better the second and third days. Always cook some extra meat as it is just fantastic the next day.