Sous-vide means cooking food sealed in a bag in water held at a precise temperature. The appeal is simple: the water is the temperature you want the food to be, so the food cannot overshoot. Edge-to-edge doneness, no grey band, no anxious poking.
That precision is real. It is also useful for a narrower range of jobs than the enthusiasm suggests.
What it is genuinely good at
Thick cuts where doneness matters. Steak, duck breast, pork chops, salmon. A 4cm steak at 54°C is medium-rare all the way through, every time.
Tough cuts over long times. Short ribs or brisket for a day or two at a low temperature come out sliceable and still pink, which no oven can do.
Eggs. 63 to 65°C for about an hour gives a white that has just set and a yolk like custard. This is the classic party trick and it is genuinely lovely.
Cooking ahead. A bag cooked, chilled fast and refrigerated, then reheated and seared, is a very good way to serve eight people something that would otherwise need last-minute attention.
What it is bad at
Anything where texture comes from evaporation or browning during cooking: roast potatoes, crackling, bread, most vegetables. Water at 85°C is a slow, wet way to cook a carrot.
It is also slow for a weeknight. An hour for a chicken breast that a pan does in twelve minutes is only worth it if the hour is unattended and you are doing something else.
Temperatures worth knowing
- Steak: 52°C rare, 54 to 56°C medium-rare, 60°C medium.
- Chicken breast: 62 to 65°C, one to two hours, for meat that is safe and still juicy.
- Salmon: 45 to 50°C for silky, 52°C for flaking.
- Pork chop: 58 to 60°C.
- Short rib: 60°C for 48 hours, or 75°C for 12 if you want it more traditionally braised.
Thickness sets the time, not weight. A thin steak is done in under an hour; a thick one takes two.
The sear is not optional
Food out of the bag is pale and slightly damp, and it tastes flat because nothing has browned. Dry it thoroughly with kitchen paper, then sear in a very hot pan for under a minute a side, or with a torch.
Dry, hot and fast. A wet surface steams and refuses to colour, and a long sear starts cooking the perfectly cooked interior you spent an hour on.
Food safety, briefly but seriously
Low-temperature cooking is safe when time and temperature go together: pasteurisation happens faster at higher temperatures and slower at lower ones. Below about 55°C, food is in the range where bacteria multiply, so long cooks at very low temperatures need care and a reliable reference table rather than guesswork.
Chill anything you are not eating immediately in iced water and refrigerate it fast; do not let a bag cool slowly on the side. Follow guidance from a food safety authority rather than a forum, especially for poultry, and treat anything intended for someone pregnant, elderly or immunocompromised with extra caution.
Bags and kit
An immersion circulator and a deep pot is all you need; a vacuum sealer is convenient but not required. Zip bags work using the water displacement method: lower the open bag into the water so pressure pushes the air out, then seal it above the waterline. Use bags rated for cooking temperatures.
Is it worth buying?
If you cook expensive cuts often, entertain, or want to prepare food ahead without stress, yes. If you mostly cook vegetables, pasta and quick weeknight dinners, a decent instant-read thermometer gives you most of the same confidence for a fraction of the price and none of the counter space.