How do I cook sous vide at home?

Sous vide is often presented as a chef's trick and it is really a very simple idea: if the water is at 55°C, nothing in it can go above 55°C, so the food arrives at exactly that and then stops. That removes the timing anxiety from steak, chicken breast and eggs entirely, and it is genuinely useful for cheap tough cuts held for many hours.

Safety

What you'll need

• An immersion circulator, or a well-controlled slow cooker and a thermometer
• A deep pan, stockpot or plastic tub
• Zip-seal freezer bags or a vacuum sealer
• A very hot heavy pan or a blowtorch for finishing
• A rack or clips to keep bags submerged

Step by step

1. Set the bath to the finished temperature you want, not higher.This is the whole method. Steak at medium-rare is around 54–56°C; chicken breast around 63–65°C; pork loin around 60°C; salmon around 45–50°C for a soft set. The food ends at the water temperature, so choose the number you want on the plate.
2. Season and bag the food.Salt it, add any aromatics — a sprig of thyme, a smashed garlic clove, a knob of butter — and put it in the bag in a single layer. Do not overfill; the water has to reach all sides. Strongly flavoured aromatics go much further in a bag than in a pan, so use less than you think.
3. Expel the air using water displacement if you have no vacuum sealer.Seal the zip bag all but one corner, lower it slowly into the water and let the pressure push the air out through the gap, then seal the last corner just above the water line. This works as well as a vacuum for anything that is not going to be stored.
4. Bring the bath to temperature before the food goes in, and keep everything submerged.Let the circulator reach the set point and hold it before you start timing. Bags that float have air trapped in them or are lifting; weigh them down with a spoon, a rack or a heavy plate. Any part of the food above the water is not being cooked.
5. Hold for the right time, which is a range not a deadline.A 2.5cm steak needs about an hour to reach temperature and is fine for up to about four. A chicken breast is an hour to an hour and a half. Tough cuts — brisket, short rib, shin — are where sous vide is remarkable, held for 24 to 48 hours at 60–65°C until the collagen has dissolved but the meat is still pink and sliceable.
6. Cover the bath for long cooks.Water evaporates, the level drops and eventually the circulator alarms or the food is exposed. Cling film over the surface, a lid with a slot cut, or a layer of ping-pong balls all cut evaporation substantially and reduce the running cost.
7. Dry it thoroughly and sear hard.Food out of a bath is wet and grey. Take it out, blot every surface completely dry with kitchen paper, then sear in a smoking-hot heavy pan for 45–60 seconds a side, or use a blowtorch. Because the inside is already at final temperature, the sear must be fast and fierce — a slow one overcooks a band under the surface.
8. Serve straight away, or chill fast if you are not eating it now.If it is not going on the plate, drop the sealed bag into iced water until cold right through, then refrigerate. Do not let it cool slowly on the counter, and do not hold it warm for hours after cooking.

Tips

• Sous vide does not tenderise a tender cut. A fillet steak is not improved much; a bavette, a chuck or a shin is transformed. Spend the effort where the cut is tough and cheap.
• A slow cooker on its keep-warm setting with a thermometer in the water and the lid propped can hold roughly the right range for firmer cuts, but it drifts and it will not hold a precise 55°C for a steak.
• Do not bag garlic raw for very long, low-temperature cooks with oil and then store it — that combination is the classic conditions for botulism. Cook it and eat it, or leave the garlic out.
• Vegetables need much higher temperatures than meat — around 85°C — because their structure only breaks down above that. They cannot go in the same bath as a steak.

Common mistakes

• Skipping the sear — The bath cannot brown anything, so the food comes out uniformly cooked and completely bland on the surface. The sear supplies all the roasted flavour and the texture contrast.
• Searing a wet piece of meat — The water has to boil off before the surface can brown, and that time is enough to overcook the outer few millimetres of something already at final temperature. Blot it properly first.

Questions people ask