Cold smoking and hot smoking are two different methods for handling meat after it has been butchered. The big difference between them is that one method involves heat, while the other does not. Both will impart flavor to the meat, but hot smoking also cures it, creating a shelf-stable meat which can be stored in more varied conditions than cold smoked meat. In addition to cold smoking and hot smoking, meats can also be cured through brining, salting, wind drying, and combinations of these techniques.
When meat is hot smoked, it is enclosed in a smoker along with a fire or pit of coals. Aromatic woods such as cedar, hickory, or apple, among others, are added to the fire so that they will generate strongly scented, flavorful smoke. The heat from the fire or coals cooks the meat, curing it so that it is less likely to decay, while the smoke penetrates the meat, infusing it with a rich flavor. It is not uncommon to marinate or brine meats before hot smoking them, to add flavors like honey or sugar.
When meat is subjected to cold smoking, it is also hung in a smoker, but the smoke is generated in a separate chamber and the temperature is kept much lower, typically a little warmer than ambient room temperature. The cold smoking process can take days or weeks, as the smoke slowly penetrates the meat without heat. Since cold smoking does not cure meats, they are usually salted or brined before being cold smoked. The salt cure ensures that the meat will stay bacteria free.
Cold smoked meats tend to taste very salty, and their texture varies, depending on how long the meats are smoked. Lightly smoked meats such as lox will have an almost raw, meaty texture, for example. Many cold smoked foods such as bacon need to be cooked before they can be eaten, to ensure that no bacteria is present. Sausages and ham are often hot smoked, so that they are ready to eat right out of the smoker.
In some cases, cold smoking may be combined with wind drying. This is accomplished by hanging meat to dry while also keeping a low level fire burning so that the meat is smudged with smoke as it cures. Wind dried foods like jerky and biltong can keep very well, since the wind drying removes much of the risk of bacterial contamination. These meats can also be eaten without cooking, as the curing process has essentially cooked them, albeit very slowly.
Probably the most important thing to remember when contrasting cold smoking and hot smoking is that hot smoked foods are generally safe as is, while cold smoked foods may be at risk of contamination. These foods should be kept under refrigeration to ensure that they stay edible. Since the techniques for cold smoking and hot smoking are slightly different, they also require different cooking skills, and cooks should approach cold smoking with care, as it is easy to contaminate food.