Smoking

Cold and hot smoking are different processes

This is the single most useful distinction on the page.

Cold smoking

Smoke only, at a temperature low enough that the food does not cook. The food comes out raw, flavoured and partly dried. Smoked salmon, cold-smoked bacon, smoked cheese. Always preceded by a cure, because the food spends hours in a temperature range where it is not protected by heat.

Hot smoking

Smoke and enough heat to cook. The food comes out cooked and flavoured, with a firmer texture. Hot-smoked salmon (flaky, opaque, quite unlike the cold-smoked kind), smoked mackerel, barbecue brisket.

How to tell them apart on a plate

Cold-smoked salmon is translucent, silky and slices thin. Hot-smoked salmon is opaque and flakes. They are sold beside each other and are not substitutes.

Which needs more care

Cold smoking, decisively. It relies on the cure that preceded it rather than on heat, and it is not something to improvise.

What smoke is doing

Smouldering wood — not burning wood, which is a different chemistry — produces a complex aerosol of compounds from the breakdown of cellulose, hemicellulose and lignin. Several groups of them matter.

Phenols carry most of the smoky flavour and are also antioxidant, so they slow fats going rancid. Carbonyls contribute colour and the glossy surface of smoked food, reacting with proteins on the surface much as browning does. Acids lower the surface pH slightly. Several of these are antimicrobial, which is the preserving half of what smoke does.

Smoke also dries the surface, and in a traditional smokehouse that drying was a substantial part of the preservation. The surface skin that forms — the pellicle — is what smoke adheres to, which is why cured fish is left to air-dry before it goes in.

What smoke does not do is preserve the inside of a piece of food. Its effects are largely at the surface, which is why smoking is nearly always paired with curing rather than used alone.

The woods, and what they suit

Wood choice is real but secondary — how much smoke and for how long matters more.

• Oak — the British and northern European default. Medium-strong, rounded, good with everything. Traditional for salmon and bacon.
• Beech — mild and clean. Common in Germany for sausage and ham.
• Alder — light and slightly sweet. The traditional wood for salmon on the Pacific coast.
• Apple, cherry, pear — mild, sweet, fruity. Excellent with pork and poultry, and forgiving if you over-smoke.
• Hickory — strong and bacony. The American barbecue standard for pork.
• Mesquite — very strong and slightly bitter. Easy to overdo; better for short, hot cooking than for long smokes.
• Whisky, wine and beer barrel oak — oak plus whatever the barrel held. Genuinely different and worth trying.
• Never resinous softwood — pine, spruce, fir. The resins produce acrid, unpleasant smoke.
• Never treated, painted or reclaimed timber. What is in the wood ends up in the food.

Smoking at home, and the honest limits

Hot smoking is very approachable. A stovetop smoker, a kettle barbecue with the coals to one side, or a foil parcel of wood chips under a rack in a lidded pan will all hot-smoke fish, chicken, cheese or vegetables perfectly well. The food is being cooked, so the usual rules about cooking it properly apply and nothing unusual is being asked of the technique.

Cold smoking is a different proposition. The food sits for hours at a temperature that neither cooks it nor refrigerates it, and it is safe because it was cured first, to a specific recipe, and because the smoker is kept below a specific temperature. Both of those are numbers, and they are safety numbers. FoodHQ does not publish salt percentages, acidity figures, processing times, curing quantities or keeping windows. Those are safety numbers set by a food safety authority rather than by a cookery writer. In the UK the Food Standards Agency is the authority — take the figures from them or from a body of equivalent standing, and use this page to understand what those figures are doing.

Liquid smoke deserves a mention rather than a sneer. It is condensed smoke from the same smouldering process, filtered — not a synthetic flavouring — and it is a genuinely useful way to get smoke flavour into a marinade, a sauce or a dish that never goes near a smoker. It does no preserving and no drying, and it is easy to use too much of.

Common questions