Cold smoking in a kamado: cheese, salmon and butter

In hot smoking, the smoke goes along with the cooking. The hot-smoked mackerel is made with the chamber at 105-130 °C until the loin reaches 62-65 °C, and the guajillo salmon is smoked at 130 °C until it reaches 60 °C in the centre.

In cold smoking there is no cooking. The food comes out as raw as it went in; what changes is its surface, where the smoke aromas settle, and its moisture, which drops a little. The FDA sets the ceiling for the chamber in industrial cold smokehouses at 32 °C, and the University of Alaska guide warns that around 35 °C the fish starts to cook.

That gives the most important idea in this guide: cold smoke does not pasteurise or kill anything, neither bacteria nor parasites. What protects a cold-smoked salmon is what comes before, freezing and salt curing, and what comes after, a cold fridge and a few days.

This guide works with two figures: 30 °C as the ceiling, the limit in the woods guide, and 25 °C as the target, the one in the cheese recipe. With cheese, the recipe opens the dome as soon as it passes 25 °C; with everything else, between 25 and 30 °C you carry on keeping watch, and above that you stop.

Two devices do the job, both with a small ember that advances slowly:

- Maze generator, such as the Weber 17636 base: a 20 x 20 cm tray with a spiral channel that you fill with sawdust and light at one end. It fits any kamado from 33 cm. - Pellet tube, such as the Naisfei 15 cm: a perforated 304 steel cylinder that you light with a blowtorch, leave to flame outside for a few minutes and then put in with the flame out, on ember alone; handle it with a glove or tongs, because the steel gets hot.

The device goes on the charcoal grate, empty and ash-free, to one side, and the food goes above, on the grid, with the pieces spaced apart. The vents are the opposite of cooking: bottom vent open one centimetre and top vent half open, as in the cheese recipe. If you close down as you would for low and slow, the ember suffocates. If the smoke comes out white and dense, open the bottom; the guide to bitter smoke explains why.

Two conditions: the kamado completely cold, because the ceramic stores heat for hours, and always outdoors, because a sawdust ember in a closed box produces carbon monoxide even if the charcoal is out.

What decides things is a probe measuring ambient temperature at the height of the food, not the dome thermometer. A multi-probe wired thermometer such as the ThermoPro TP17H, with a stated range from -10 °C, measures the chamber and the air outside at the same time; the thermometer guide explains where to place it.

The table in this guide gives the normal climatological values of AEMET (the Spanish state meteorological agency) for the Alicante station, 1981-2010 period. The generator adds some heat, so working at 25 °C needs cooler air, and shade.

From December to February, with average highs of 17-18 °C, you can do it at any hour in the shade. March is good too: an average high of 19.6 °C, keeping an eye on the midday sun. November and April, at 20-21 °C, give you the night and the morning, and the afternoon in the shade is marginal. October and May are for night or first thing: their average highs are around 24-25 °C. May is slightly cooler than October but sunnier: 277 hours a month against 217, according to the same AEMET table, and a dome in the sun feels it. From June to September the average lows run from 18 to 21 °C: that leaves the early hours, and not for fish.

Four things move the figure:

- Shade. A dark dome in the sun heats up well above the air temperature. - Ice. A tray of ice on the grid, next to the food, takes heat out, but as it melts the humidity rises. - Humidity. The Alaska guide considers cold smoking not possible when relative humidity cannot be brought below 75%. According to AEMET, the Alicante average runs from 63% to 70%, but the sea wind pushes it up; the Levante wind has its own section in the guide to the kamado in winter. - Averages are averages. The table says which months; the probe says whether today is the day.

Above 30 °C cheese sweats fat and fish spends hours in the range where bacteria grow best: open the dome and, if it does not come down, stop and put everything in the fridge. Nor is anything below it a safe zone: according to the Alaska guide, the whole of cold smoking takes place in the danger zone, 4 to 60 °C, so the fish goes in cured and cold and back into the fridge as soon as it comes out.

With raw fish there are four rules from official sources.

Anisakis: freeze first. AESAN (the Spanish food safety agency) lists "marine fish subjected to cold smoking" among the home preparations that must be frozen. At home, -20 °C or lower for at least five days, which only a three-star freezer or better guarantees; if yours is less than that, buy the fish already frozen. Industry follows Regulation (EC) 853/2004: -20 °C for 24 hours or -35 °C for 15 hours.

Listeria: who should not eat it. According to AESAN, smoked fish is among the foods most associated with listeriosis, because the bacterium grows even in the fridge. For pregnant women, children, older people and the immunocompromised, the official recommendation is to avoid smoked fish.

Botulism: beware of vacuum. According to the FDA's guidance for fishery products, Clostridium botulinum type E grows without oxygen from 3.3 °C. Industry holds it back with at least 3.5% salt in the water phase of the fish; at home you cannot measure that, so home-made vacuum-packed salmon goes in the freezer.

Cold and a few days. The Torry advisory note gives 5-6 days below 4 °C for commercial smoked salmon. A home-made salmon should not go beyond that.

And one red line: do not cold-smoke raw meat to eat it as it is. It gets cooked afterwards, like the home-made pastrami: brine, smoke and steam.

The cheeses that work are firm-textured, cured or semi-cured: semi-cured Manchego, Gouda or block mozzarella, the pizza kind, which are the ones in the recipe. Fresh and soft cheeses are not worth it: they deform with little heat, and AESAN cites soft-textured ones among the foods associated with listeria.

Cut blocks 3-4 cm thick: thinner ones get saturated, thicker ones leave the centre without smoke. Remove any paraffin or plastic rind. Take the cheese out of the fridge 30 to 60 minutes beforehand and pat it dry with kitchen paper, because an ice-cold cheese condenses water and that film makes the smoke bitter.

The cold-smoked cheese recipe gives 2 hours for mozzarella and 2.5 to 3 hours for Gouda and Manchego, with the chamber below 25 °C. There is no official figure; look for an even golden colour.

What people forget most is the resting time. Straight out of the smoke it tastes like an ashtray; wrapped and in the fridge, the smoke migrates inwards. The recipe asks for several days and no rule fixes the time: try one piece early and leave the rest for up to two weeks, always within the cheese's date.

Salmon is the one that asks for the most steps:

- Freeze. Five days at -20 °C, as AESAN requires, or a loin bought already frozen. Thaw it in the fridge. - Cure in salt. The Torry note describes the industrial method: fillets covered in dry salt for about 12 hours for those from a 4 kg salmon and 24 hours for those from an 8 kg one. For a loin 3-4 cm thick, between 12 and 24 hours in the fridge is an indicative range. - Rinse and dry. Rinse, pat dry and leave the loin uncovered in the fridge, below 3.3 °C. The Alaska guide gives 2 to 24 hours of this rest for the salt to even out, 6 to 8 for a 2.5 cm fillet, and the surface starts to dry during it. The pellicle, a tacky, glossy layer, is finished with a little more warmth: the guide forms it in the smokehouse, over 30 minutes to 3 hours. - Smoke. In Torry's industrial kiln, at 27 °C, salmon has enough flavour and colour at around 5 hours. In the kamado, 4 to 6 hours of smoke is a starting point with the probe at 25 °C and never above 30 °C. The Alaska guide, written for home smokehouses, talks of 16 hours to 7 days depending on the product: treat all of it as a guide. - Slice. A few hours in the fridge settle it and it slices better. A long, flexible-bladed salmon slicing knife gives thin slices.

Keep it below 4 °C and for a few days; for longer, sliced and frozen, which the Alaska guide puts at 2-3 months at home. If that seems like a lot, the guajillo salmon is the shortcut: it reaches 60 °C, and AESAN considers that 60 °C for one minute throughout the piece destroys anisakis.

Do not start with salmon: learn on foods that are already stable before they meet any smoke.

Flaked salt is the safest: AESAN cites it, along with sugar and honey, among the foods in which listeria cannot grow. Cold butter, in a block, is the first to warn you if the chamber is heating up. Nuts, paprika and other dry spices have no free water to worry about. Oil takes smoke too; the risk comes if you then put garlic in it: AESAN cites home-made preserves in oil among the foods associated with botulism, so smoked garlic in oil goes in the fridge and is used up soon.

The hours for salt, butter, nuts and spices are indicative, with no official source: check every half hour.

Generator or tube. The Weber base is designed for sawdust: the channel is narrow and the fine dust burns evenly. The Naisfei tube runs on pellets. Neither spec sheet gives a burn time you can stand behind: Weber says smoke "for hours" and Naisfei gives no figure, because it depends on the fuel and the airflow.

Sawdust or pellets. For the base, a beech flour for cold smoking, with a grain of 0.5 to 1.0 mm according to its spec sheet. For the tube, the 6 mm BBQ-Toro apple pellets, which are the ones in the cheese recipe, or the Weber alder pellets, the classic smoke for salmon. No heating pellets, which are not intended for food. Which woods are always off limits, and why, is covered in the guide to smoking woods.

What does not work. Wood chips and chunks are for hot smoke, over the embers. A smoker box like the La Cuisine one does not either: it needs embers underneath for the chips to smoulder.

The probe. Any probe thermometer whose range starts below 10 °C will do: in winter the chamber drops under that and, if yours starts higher, you will not see it warming.