Many cuts of beef, pork or seafood benefit significantly from exposure to the smoke of smoldering hickory, mesquite, pecan or apple wood. Achieving this effect indoors without a smoker, however, can be quite a challenge. A concentrated seasoning known as liquid smoke is often used to duplicate the appealing flavor and aroma of real smokehouse wood without the need for a real smokehouse. Liquid smoke is derived from actual smoke generated under controlled conditions from popular woods used for outdoor barbecuing and smoking.

The production of commercial liquid smoke begins with the proper wood. Mesquite or hickory have both been associated with meat barbecuing for decades, while regional woods such as pecan or apple wood have recently grown in popularity. To make liquid smoke, a supply of wood is placed inside a large oven known as a retort. The wood itself is not burned to create the smoke, but intensely heated by another source to create a slow smolder. This smoke is then drawn out of the retort for further processing.

The smoke at this point is composed of tiny smoke particles held in water vapor. A refrigeration unit rapidly chills the surrounding air, which causes the smoke particles and water to condense and fall as a liquid. This liquid smoke is then piped into oak barrels for aging, much like a distilled bourbon whiskey or oaked wine.

Following the aging process, the concentrated liquid smoke is filtered to eliminate any impurities, then bottled for shipping. Bottles of liquid smoke can usually be found near other liquid seasonings and condiments such as Worcestershire sauce and Angostura bitters. Much larger containers of liquid smoke can also be purchased for commercial use in restaurants and meat processing plants. Liquid smoke is also a common ingredient in many barbecue sauces featuring hickory or mesquite flavor enhancements.

Because liquid smoke is so concentrated, most recipes only call for a few drops to taste. Canned smoke is usually added to a meat marinade or sauce, rarely on the meat itself. Certain varieties of liquid smoke may be better suited to specific types of meat, as in the case of apple wood with cured ham, or hickory with pulled pork. Pecan liquid smoke often works well with seafood, but may not be strong enough to enhance a beef tenderloin, however. Some recipes may suggest a specific flavor of liquid smoke, while others may make the addition of liquid smoke optional.

There is some debate over the use of liquid smoke in place of a real wood smoker. Barbecue purists generally dismiss liquid smoke as a poor substitute for real hardwood smoke, while others see very little difference between the two sources of smoke flavor. Too much liquid smoke can indeed overwhelm or even ruin the flavor of barbecued or grilled meat, but too much time in a traditional smoker can also be problematic. Liquid smoke does not usually contain any other ingredients besides natural smoke and water, but some diners can still tell the difference between natural and liquid smoke. When in doubt, it might help to buy the highest quality liquid smoke available and use it sparingly to enhance a sauce or marinade.