Sous vide
Seal the food, drop it into water held at the exact temperature you want it to reach, and wait. It is very hard to overcook anything this way.
Why it works
In a pan or oven the heat source is far hotter than the doneness you want. A 220 °C oven taking a steak to 55 °C means the outside races past done while the centre catches up. That is where the grey band under the crust comes from, and why timing a roast is so stressful.
Sous vide removes the gap. The water is held at the target temperature, say 55 °C, so the food can only ever reach 55 °C. Leave it a little longer and almost nothing happens. Water carries heat far better than air, so the food cooks evenly from edge to centre, and the bag keeps moisture and flavour in rather than letting them evaporate.
Time still matters, in two ways. It takes time for heat to reach the centre, which depends mostly on thickness, not weight. And time changes texture: hold meat long enough and its proteins and collagen slowly break down. A tough short rib needs days to turn tender at a temperature that keeps it pink, while a chicken breast or a piece of fish goes soft and mealy if you forget it.
What you give up is browning. Water never gets anywhere near the 140 °C or so the Maillard reaction needs, so most meat finishes with a fast, very hot sear. Treat the bath as the part that gets the inside right, and the pan as the part that makes it taste roasted.
What you need
- Immersion circulator: Clips to a pot, heats the water and keeps it moving, holding the temperature to within about 0.1 °C.
- Deep pot or container: Big enough for the bags to sit fully under with water flowing round them; 8–12 litres suits most home cooks.
- Freezer-grade zip bags: Fine up to about 70 °C for a few hours; use vacuum bags for long or hot cooks.
- Vacuum sealer: Gives a tighter, more reliable seal for cooks over 24 hours and for food you plan to chill and store.
- Clips or a weight: A binder clip on the pot rim, or a heavy spoon in the bag, stops bags floating.
- Heavy pan or blowtorch: Cast iron or carbon steel, heated as hot as you can get it, for the sear.
- Probe thermometer: Useful for checking the bath now and then, and the core of thick cuts when you are unsure.
Step by step
Heat the water
Fill the pot, clip on the circulator and set the temperature from the finder below. Hot tap water gets you there faster. Make sure the water sits between the minimum and maximum lines on the circulator.
Tip: For anything over two hours, cover the pot with a lid, cling film or a layer of ping-pong balls. You lose far less water and heat, and the circulator will not cut out overnight.
Season simply
Salt, pepper, a sprig of thyme or rosemary, a knob of butter. Go easy, because flavours concentrate in the bag. Leave out raw garlic for long cooks; at low temperatures it can turn harsh. Alcohol does not cook off in a sealed bag, so reduce any wine first.
Tip: Salt steak up to a day ahead and leave it uncovered in the fridge. The surface dries, so the sear later is quicker.
Bag it with the air out
Lay the food flat in a single layer so heat reaches it evenly. No sealer? Use the water displacement method: put the food in a zip bag, close all but one corner and lower the bag slowly into the water. The pressure pushes the air out through the gap; seal the corner just above the waterline.
Tip: Fold the top of the bag back over itself like a cuff while you fill it, so the seal stays clean and closes properly.
Submerge and cook
Once the water is at temperature, lower the bag in. Every part of the food should be under water, with room for water to move around it. Clip the bag to the side or weigh it down if it floats. Start timing when the bath is back at temperature.
Check the clock, not the colour
Use the finder for the window that suits what you are cooking, and the thickness table for how long the centre needs to come up. Anything in the window is fine. Going past the end of the window makes the texture softer, not dangerous, unless you are below 54 °C.
Dry it, really dry
Take the food out of the bag and keep the juices for a sauce. Pat every surface dry with kitchen paper. Any moisture has to boil off before a crust can form, and that time is what overcooks the outside.
Tip: For a thinner grey band, chill the sealed bag in iced water for 10 minutes before searing. The cooler outer layer buys you extra seconds in the pan.
Sear hard and fast
Smoking-hot pan, a thin film of oil with a high smoke point, 45–60 seconds a side. Add butter and herbs for the last 20 seconds and spoon them over. You are only browning the outside; the inside is already done.
Tip: Thick cuts with a fat cap, such as duck or lamb rack, want slower rendering on the fat side first, then a quick sear on the rest.
Serve straight away
No resting is needed. The meat is the same temperature all the way through, so it will not lose juice when you slice it. Warm the plates, because sous vide meat is served at its cooking temperature and cools quickly.
Thickness and minimum time
| Thickness | Minimum time at 55 °C |
|---|
| 1 cm | 15 min |
| 2 cm | 45 min |
| 2.5 cm | 1 h |
| 3 cm | 1 h 20 min |
| 4 cm | 2 h |
| 5 cm | 3 h |
| 6 cm | 4 h 15 min |
Troubleshooting
The bag keeps floating
There is air trapped inside, or the food gave off gas during a long cook. Reseal using the displacement method, or put a heavy spoon or small jar in the bag and clip the bag to the pot. A bag that floats partly out of the water cooks unevenly, and on a long cook that is a safety problem.
A grey band under the crust
The sear went on too long, usually because the pan was not hot enough or the meat was wet. Dry it harder, get the pan hotter, and chill the bag in iced water for 10 minutes before searing.
Chicken or fish turned mushy
Lean, delicate proteins break down if they sit too long. Keep chicken breast under 4 hours and fish under 1 hour. Tough cuts like short rib are the opposite: they need days.
The circulator stopped overnight
The water dropped below the minimum line. Cover the pot for long cooks and top up with hot water. If the bath sat below 54 °C for more than 2 hours with raw protein in it, throw the food away.
Vegetables are still crunchy
Vegetables need much more heat than meat. The pectin that holds their cells together only softens above about 83 °C, so cook them on their own at 85 °C rather than in the bath with the meat.
The meat tastes flat or slightly boiled
Nothing browned, and the seasoning stayed in the bag juices. Season a little more firmly before bagging, sear harder, and reduce the bag juices in the pan with a knob of butter to pour over.
The bag leaked
Zip bags can open at the seal on long or hot cooks, and bones can puncture vacuum bags. Double-bag anything with sharp bones, or wrap the bone ends in a little baking paper. If water got in early, the meat will taste washed out; cook it on and season the finished dish well.
Low temperature means time matters
Sous vide makes food safe through temperature and time together: at 63 °C, chicken is pasteurised by being held at that core temperature for long enough, not the instant it arrives. Below about 54 °C, bacteria are not killed reliably, so those cooks must be short.
- Below 54 °C, cook for no more than 4 hours in total.
- Keep everything fully submerged and the bath at temperature; a bag sticking out of the water is not cooking safely.
- Serve straight away, or chill the sealed bag in iced water until cold right through and refrigerate it for up to 5 days. Only do this with food cooked at 54 °C or above for its full time.
- Rare fish such as salmon at 45 °C is not pasteurised. Buy it very fresh, or freeze it first to kill parasites, as you would for sushi.
- For pregnant, elderly or immunocompromised guests, cook poultry and pork at 63 °C or above for the full time, and skip rare fish and soft eggs.
