I gave my mother a “sous vide” machine for her birthday because I’ve wanted to play with one for ages—Heston Blumenthal has said they “have the potential to be the biggest change in domestic kitchens since the microwave.” Until recently, these machines were cumbersome and expensive, strictly the preserve of commercial kitchens. But now you can buy smaller, cheaper versions and modernist foodies are adding them to their gadget collections. John Lewis reports almost tripling sales over the last two years.
Sous vide cooking involves compressing food in a vacuum-sealed bag (“sous vide,” “under vacuum”) and cooking it in a water bath kept at a precise temperature. Vacuum sealing requires a separate machine, so the home cook can use a Ziploc bag instead.
What happens to food when it’s cooking depends on the temperature and how long it’s in for. Meat cooks to rare at around 50°C, to rosy medium at 60°C and well done at 70°C. Non-leafy vegetables begin to soften at 85°C. But in the kitchen most methods subject food to vastly higher temperatures: water boils at 100°C, roasts tend to go into a 250°C oven and the oil in a frying pan is 200-250°C.
Consider your Thursday evening panfried sirloin: the outside is seared, but when you cut into it there is a layer of overcooked grey surrounding a pink juicy stripe of rare. This is because the sirloin has been subjected to high temperatures in order to force a bit of heat into the middle. It takes a lot of energy to transfer heat through a steak or a carrot; flesh is very good insulation. But a sous vide water bath can hold its temperature at precisely 57°C. Your steak goes in the bag in the water, and no part of it will ever overcook to grey, no matter how long it sits there.
I chose a machine made by a company called Anova, because instead of being a freestanding tank that takes up counter space, it’s a foot-long cyclinder that you clamp inside a pan of water to act as an immersion heater and water circulator. Also it was $200 (£120), cheap as sous vide machines go.
We decided to begin our experiments with a pork loin because, as Mum said: “It’s impossible to cook pork loin. It goes dry and has no flavour.” I filled a big saucepan with water, clamped the machine to the side, punched in the temperature (60.5°C) and time (45 minutes) and slid in a pork loin, still in its supermarket vacuum packaging. The machine made almost no noise, just a low hum. The pork bag rested on the bottom, like me sitting in a bath. No drama of spit and smoke. I almost wanted to give it a magazine to read.
Forty-five minutes later I pulled out the plastic bag with my fingers (60.5°C is hot but 39.5°C below boiling hot, after all). I tipped out the pale pork log. It was as plump as it had been before it went in. When a steak sizzles on a hot pan it is the sound of moisture being lost and the meat reduces; compressed in its bag under a mild temperature, the pork loin’s water content had been retained.
“Huh!” said Mum slicing into the pork. “It’s perfectly cooked.” “Huh!” she repeated, tasting a bite. “It’s really good.” The inside was a pretty blush colour and so tender it could have been veal. “What is this?” asked Dad spearing a peice with his fork, “Boil-in-the-bag?”
We cooked sous vide every day for a week. Next we tried lamb loin. The temperature was too low to produce a brown caramel crust on the meat, so after the water bath I seared it for a couple of minutes each side to crisp up the fat. Again, pitch perfect pink interior. We cooked monkfish (45°C, 30 minutes) and it came out glassy and buttery with a texture like a perfectly cooked scallop. Wedges of fennel and small quartered artichokes (one hour, 85°C) emerged in a new category of previously unreachable vegetable Shangri-la, firm but cooked, flavour intense and intact.
And then we tried pork ribs. Various recipes suggested either 24 or 48 hours to break down the collagen. We did 36 hours at 60.5°C. But some of the barbecue marinade must have leaked out into the water. “It looks like the great grey greasy Limpopo,” said Dad. “I can’t believe it won’t be mush after all that time,” said Mum.
“I guess not all experiments work out,” I said despondently. The ribs were swimming in brown-grey soup. I pulled one out to prod. It was weirdly, unexpectedly, firm. “They’re OK!” I said, “They’re OK!” I swabbed my everything- in-the-cupboard barbecue sauce on them (sweet salt sour and umami altogether, made out of several or all or some of the following: treacle, honey, marmalade, ketchup, hoisin sauce, teriyaki, mustard, sweet chilli…) and stuck them in a super hot oven, three minutes on each side. They came out just as you would want them, black and sticky, but not chewy and shrivelled as ribs usually are.
The control and ease of sous vide cooking is exciting and beguiling. No stress, no burnt fingers or meat thermometers or sacrificial cuts to check inside, no mess of fat splatter. Now, of course, I want my own machine. And I want a vacuum sealer, too, to cook with added flavours. And I am thinking how easy it will be to make the perfect custard if you know that egg yolks coagulate at 60°C. And what about pot-au-feu in-a-bag where no flavour can be lost to evaporation, or poaching apples in caramel for making tarte tatin or…