Is cold smoking food at home safe?

The appeal is obvious — home-smoked salmon, smoked cheese, smoked bacon — and cold-smoke generators are cheap and widely sold. What is often not said is that the smoke is a flavouring, not a preservative, and everything that makes cold-smoked food safe happened before the smoke was lit.

Safety

Step by step

1. Separate the two things smoking does.Hot smoking cooks the food as it flavours it, and the finished product is a cooked product. Cold smoking, at 20 to 30°C, only deposits smoke compounds on the surface. The food comes out raw, at room temperature, having been at room temperature for hours.
2. Understand that the cure is the safety step.Cold-smoked salmon is safe because it was salted to a specified rate for a specified time first, which drew water out and made it inhospitable. Smoke contributes a small surface antimicrobial effect and nothing more. Skip or shorten the cure and no amount of smoke compensates.
3. Take the temperature seriously.The chamber must stay below about 30°C throughout. In a British summer, or with a smoke generator in a small enclosed box, it will not without active management — which usually means ice trays in the chamber, smoking overnight, or not smoking at all that week. Above 30°C you are neither cold smoking nor cooking, which is the worst of both.
4. Know the specific hazards for specific foods.Cold-smoked fish is associated with Listeria monocytogenes, which grows at fridge temperatures. Cold-smoked meat that is not cured correctly carries a botulism risk. Cold-smoked cheese and cold-smoked salt are far lower risk because there is little for anything to grow on and the cheese is already a controlled product.
5. Follow a specific published method, end to end.One source, for one product, giving the cure rate, the cure time, the drying time, the smoke time and the storage. Do not assemble a method from several places, and do not improvise the cure because you have a smoke generator and a piece of salmon.
6. Start with something low-risk.Cold-smoked cheese, cold-smoked salt, cold-smoked butter or cold-smoked nuts give you the technique and the equipment experience with none of the meat or fish risk. Cold-smoked cheese in particular is a good first project — smoke it, then let it rest wrapped in the fridge for a week for the flavour to settle.
7. Refrigerate the result and set a short life.Home cold-smoked fish is a fridge item with days, not weeks, of life, and it freezes reasonably well. Nothing about the process makes it a cupboard item.
8. Do not serve it to anyone vulnerable.Pregnant women, babies and young children, people over 65 and anyone with a weakened immune system are advised against cold-smoked fish even from a shop, because of Listeria. Home-produced cold-smoked fish should not be served to them at all.

Tips

• A cold-smoke generator in a cardboard box does work, but it gives you no temperature control at all. If you are smoking anything that has been cured, a thermometer in the chamber is not optional.
• Smoke on a cold, still day. Wind blows the smoke away, warmth ruins the temperature, and rain puts the generator out.
• Let cold-smoked food rest wrapped in the fridge for a day or two. Straight off the smoke it tastes acrid, and it mellows considerably.
• Check the Food Standards Agency for current guidance on smoked fish and vulnerable groups before serving it to anyone at all.

Common mistakes

• Cold smoking uncured meat or fish — It is several hours in the danger zone with nothing at all standing between the food and whatever is growing in it. This is the single most dangerous thing a home smoker does, and it is common precisely because the smoke feels like it must be doing something.
• Treating cold smoking as a way to preserve food — It is not. Modern cold smoking is a flavouring process applied to food that has already been preserved by curing, and the result is refrigerated and short-lived. The historic version that did preserve involved far heavier salting and far longer smoking than anything you would want to eat now.

Questions people ask