WHILE THE IDEA OF SMOKING meats usually conjures up images of crispy bacon or a slab of barbecued ribs, the technique originated as a means of preservation before it ever caught on as a flavoring method. Smoking slowly dehydrates meat by removing a good deal of its moisture, dramatically prolonging its shelf life. Since moisture is the breeding ground for bacteria, the less water in a piece of meat, the less chance for spoilage. Traditionally, the bulk of meats were cured and smoked in the late fall, allowing for a stocked winter pantry at a time when most foods were scarce.
Before refrigerated trucks rolled around in the late 1940s, smoking presented an alternative to heavy salting ("dry curing") as a method of preserving meat, allowing it to be stored and shipped over an extended time. Now, with efficient refrigeration options available almost everywhere, smoked meats have maintained their popularity simply because of their unique flavor.
Meat may be hot or cold smoked. Hot smoking (temperatures above 165° F) not only infuses the meat with a characteristic "smoky" flavor, it also raises the meat's internal temperature—meaning the meat is safely "cooked"—and prolonged hot smoking softens tougher cuts by breaking down the connective tissues. (This concept taken to the extreme produces beef jerky, which is meat dehydrated nearly to the point of becoming leather, due to prolonged moisture loss from the smoke.) Barbecue joints hot smoke their briskets, ribs, and pork shoulders, which are ready to eat right after their lengthy smoking.
Cold smoking (up to about 100° F) is also used to impart a smoky flavor to meat, and is most commonly used to season delicate fish like salmon and leaner cuts like pork chops, whose texture would be compromised by the more intense heat of hot smoking. The biggest difference between hot and cold smoking is that cold-smoked foods needs to be either cured before they are smoked to make them edible (think smoked salmon)—since the smoking process alone will not cook them—or they need to be cooked after smoking but before eating (think bacon or smoked pork chops). The pre-smoking curing process usually involves a "dry cure," in which the meat is packed in a thick layer of coarse salt (and sometimes sugar), along with herbs and spices and allowed to sit for a few days.
This type of curing simultaneously draws excess moisture out of the meat and seasons it. The more water extracted from the meat, the richer and more concentrated its flavor will be. Adding a salt rub to pork belly or salmon before it is smoked also creates a tacky pellicle (a thin skin) on the surface of the meat, which helps the flavoring molecules adhere during the smoking process.
A seasoned cure is not the only element that affects the flavor of smoked meats—the smoke itself imparts a particular flavor and aroma. Fruit- and nut-bearing woods are most commonly used to smoke foods. Some woods are preferred for seasoning specific meats—Chef Eric Gabrynowicz of Tavern Restaurant in Garrison prefers apple wood, for example, when smoking lighter flavored meats like pork and chicken. In the Hudson Valley, popular woods for smoking include apple, cherry, hickory, and oak. (Some local apple orchards sell tree prunings for home smokers.) Hickory's strong flavor is preferred for beef. Locality often holds a strong influence over people's flavor preferences; this is no more true than in Texas, where mesquite is the wood of choice. Unfortunately, the USDA dictates that the wood chips used for smoking commercial and retails meats conform to a whole host of regulations, so most smokehouses opt to buy those stamped with their seal of approval (or risk liability), rather than harvesting local woods.
Because there are so many levels of production inherent in processing smoked meats on an industrial level, most smoked products available on a retail level are treated with sodium nitrite to help ward off bacterial contamination, fix the bright pink color of the meat, and to vastly prolong its shelf life. Sodium nitrite occurs naturally in many vegetables (lettuce, celery, tubers) but it poses a problem when it comes in direct contact with extreme heat (as in a frying pan of bacon) or a highly acidic environment (your stomach): It is converted into carcinogenic nitrosamine.
When smaller smokehouses (or home smokers) oversee the smoking process from start to finish, there usually is less risk of contamination. Some smokehouses, like Mountain Products Smokehouse, in LaGrangeville, process meats without nitrites. Tom Gray says he has plenty of customers who, citing health concerns, request nitrite-free products.
Nitrite-free meats generally have more of a brownish color (as opposed to pink), a shorter shelf life, and often a saltier flavor, resulting from additional salt being added to make up for the lack of sodium nitrite, which itself imparts a salty flavor.
When it comes to choosing the right cut of meat for smoking, think cheap and tough—the tougher the connective tissue and the more layers of fat the better. Smoking acts like braising on a rough cut, softening and melting the connective tissues during the prolonged hot smoking process. It should be no surprise that tough Boston butts, shoulders, briskets and ribs are the most commonly smoked cuts.
Top-quality smoked meats are smoked in small batches under the careful eye of a smoke-master. (To smoke meat for retail requires a license, so small farmers send their meat out to be butchered and smoked off-site, even if the finished product is sold directly at the farm.) Good smoked meat will be a burnished mahogany on the outside and deep reddish-pink inside. A dark pink "smoke ring" also occurs in all smoked meats—look for the distinct coloring just under the exterior or skin. It occurs when meat has actually been smoked over a fire. Poorer quality "smoked" supermarket meats may not be smoked at all, and are often cured with smoke flavoring instead of actually coming in contact with smoke and are usually unnaturally bright pink in color.
"Liquid smoke"—literally smoke that has been liquefied through sudden chilling and available bottled—also comes in various qualities; make sure to read the labels so you are buying a "real" product instead of one filled with chemical smoke flavorings. Supermarket / industrial processed ham hocks and most commercial bacon are both good examples of smoke-flavored meats. Search out the real thing whenever possible.