While cookbooks and smoking fanatics alike differ on what specific temperature delineates a hot versus a cold smoke, Paul Kirk, also known as the Kansas City Baron of Barbecue, says that “at the low temperatures of a cold smoke, all you’re doing is flavoring the meat or ingredient with smoke, whereas with a hot smoke, you’re both flavoring and cooking it simultaneously.” He marks a cold smoke as below 100 degrees Fahrenheit, while for Elizabeth Karmel, founder of the website Girls at the Grill and author of Taming the Flame: Secrets for Hot-and-Quick Grilling and Low-and-Slow BBQ, a cold smoke lies between 90 and 120 degrees Fahrenheit. Bacteria breed fast at temperatures under 140, so hot smoking is generally understood to lie between 165 and 185 degrees Fahrenheit, though Karmel finds the optimal hot smoking temperature to be between 275 and 300 degrees Fahrenheit, where fat “turns into liquid and makes the meat moist and meltingly tender.”
Harold McGee, culinary scientist and author, explains a further distinction in On Food and Cooking: The Science and Lore of the Kitchen: Hot-smoked products are smoked in the same chamber as the burning wood, whereas cold-smoked products are held in an unheated chamber through which smoke is pumped (the smoke originating from an external firebox).
While traditional hot and cold smoking used to be limited to proteins, contemporary chefs are experimenting with the technique in innovative ways. Portland bartender Evan Zimmerman hot-smokes ice, then refreezes it to use as cubes in his cocktails, and Chef Daniel Humm of Eleven Madison Park cold-smokes yogurt: “We serve it with a light salad, and the smokiness is a nice addition to the dish. It reminds me of summer.”
A general rule of thumb: Cold-smoke ingredients to impart a smoky flavor to food that doesn’t need to be cooked (e.g., dairy products like butter or cheese) or that you plan on cooking later, on the grill or in the oven; hot-smoke ingredients to both flavor and cook them (e.g., meats). See CHOW’s recipes for smoking.