Two entirely different products under one name. Cold-smoked fish is cured but essentially raw, silky and sliceable; hot-smoked fish is cooked through and flakes. Lox is neither — it's salt-cured with no smoke at all.
Cold smoking holds the fish below about 85°F, so smoke flavours and further dries it without cooking — the flesh stays translucent and is sliced paper-thin across the grain. Hot smoking runs at 160-225°F and cooks the fish through, giving opaque flesh that flakes. Salmon is the dominant fish for both, with mackerel, trout and haddock common for hot smoking. Kippers are herring split, brined and cold-smoked. Lox is salt-cured belly with no smoke; gravlax is cured with salt, sugar and dill, also unsmoked. Nova is cold-smoked and mildly cured, which is what most people actually buy calling it lox.
Cold smoking depends on the cure for safety rather than on heat, since the fish never reaches a pasteurising temperature. Salt lowers water activity and the smoke contributes phenols and formaldehyde compounds that are mildly antimicrobial and slow oxidation. Because the fish stays raw, commercial cold-smoked salmon is required to be frozen first to a specified time-and-temperature to kill parasites, which is why home cold-smoking carries real risk if that step is skipped. Hot smoking pasteurises directly. The pellicle — a tacky protein surface formed by air-drying the cured fish for a few hours — is what smoke adheres to, and skipping it gives weak, uneven smoke flavour.
It's cured and ready. Slicing thin across the grain is the only technique involved.
HowPaper-thin slices at a shallow angle. With bagels and cream cheese, or with blini, or just lemon and pepper. Never cooked — heat turns it firm and fishy.
It's fully cooked and its texture suits being broken up rather than sliced.
HowFlaked into scrambled eggs off the heat, into a pasta with cream and dill, into a chowder at the last minute, or blitzed into a pâté with cream cheese and horseradish.
It's the one member of the family that requires no equipment and no smoke — just salt, sugar and time.
HowEqual salt and sugar, roughly 100g of each per kilo of fish, with dill and crushed pepper. Wrapped and weighted in the fridge for forty-eight hours, turning once. Rinse, dry, slice thin. Use commercially frozen fish.
Straightforward with any smoker or a kettle grill, and hot smoking pasteurises so the safety margin is far wider than cold.
HowBrine at 5% for two hours, dry uncovered until a tacky pellicle forms — two to four hours — then smoke at 175-200°F to 140°F internal, about an hour and a half.
Cold-smoked salmon has been cured and smoked below cooking temperature specifically to stay silky and translucent, and applying heat to it undoes all of that — the proteins contract, the texture turns firm and dry, and the concentrated cure comes forward as an aggressive fishy saltiness. Add it to hot dishes off the heat at the very end, or not at all. The second point is a genuine safety matter rather than a quality one. Cold smoking never reaches a temperature that kills parasites, so commercial producers are required to freeze the fish first to a specified schedule. Home cold-smoking fresh, never-frozen fish skips the only parasite control in the process. Use commercially frozen fish, or hot-smoke instead, which pasteurises.
Know which you're buying: cold-smoked and lox are translucent and sliceable, hot-smoked is opaque and flakes. For cold-smoked salmon, look for even colour without white streaks of congealed albumin, which indicates it got too warm. It should smell clean and faintly of smoke, not fishy. Wild versus farmed changes the texture more than the flavour — wild is leaner and firmer. Sliced-to-order from a good counter beats vacuum packs. Hot-smoked mackerel and trout are excellent, cheap and underrated. Cold-smoked keeps about five days opened; hot-smoked a little longer.
Doneness: Cold-smoked is held below 85°F and served cold, never heated. Hot-smoked is cooked to 140°F internal and can be eaten warm or cold. If hot-smoking at home, brine, form a pellicle, then smoke at 175-200°F to 140°F.
Lox is strictly salt-cured belly with no smoke at all, and it's very salty. Nova — short for Nova Scotia — is mildly cured and cold-smoked, which is what most delis sell and most people mean when they say lox. Smoked salmon without qualification usually means cold-smoked. Gravlax is Scandinavian, cured with salt, sugar and dill, also unsmoked. All are sliced thin and eaten cold.
Yes, and it's much more forgiving than cold smoking, because the fish reaches 140°F and is pasteurised. Brine it, air-dry to form a pellicle so the smoke adheres, then smoke at 175-200°F. Cold smoking at home is where the risk lies, since nothing in the process kills parasites — that requires commercially frozen fish.
That's albumin, the water-soluble protein that coagulates and is squeezed out when fish is heated too fast or too far. On hot-smoked fish it means the smoker ran too hot. On cold-smoked fish it shouldn't appear at all, and if it has, the product got warm during smoking or storage. A gentle brine and lower temperature both reduce it.