This article was first published in the August 2015 issue of WIRED magazine. Be the first to read WIRED's articles in print before they're posted online, and get your hands on loads of additional content by subscribing online
The art of sous vide -- vacuum-packing food then slow-cooking it at a low temperature for optimum results – has been used in restaurants for decades. Sarah James, editor of sousvidely.com, tells us how to get the most from this culinary technique.
Build a water bathThe first step is to find a container suitable for cooking boil-in-a-bag style. James recommends starting off by souping up a stockpot. This works for steaks or fillets of fish, but when you're ready to graduate to a rack of ribs or whole chicken, you'll need something bigger. Once James outgrew her stockpot, the next stop was a transparent polycarbonate box. Polycarbonate has the added advantages of retaining heat and withstanding high temperatures – and the boxes come in all shapes or sizes. Go for a 25-litre box if you have something ambitious in mind (Heston Blumenthal cooked a pig sous vide).
Regulate the waterYou can maintain the cooking water temperature for a couple of hours or more using an immersion circulator, which heats and regulates, but it is expensive. Food that doesn't need cooking for long periods can be done in a big sink. The inside of a salmon fillet needs to reach only 48°C, which can take just 20 minutes. And if a big sink is filled with hot water around 50-52°C it will hold that temperature for half an hour. James says a cool box is another good receptacle: "Just heat up the water a few degrees hotter than you want -- because it will cool when you add the food," she says. "Fish, steak, chicken and chops all work well with this method."
Out of the vacuumProfessional kitchens use embossed bags and vacuum sealers to pack their food before immersing it. "Water conducts heat 20 times more efficiently than air," James says, explaining why it's important to squeeze out all or as much air as possible. "If you have pockets of low-temperature air surrounding your meat and are cooking at a low temperature it can be dangerous." To avoid this, simply place the steak, fillet or vegetables in an unsealed freezer bag and lower into the water bath. "All the air gets forced out," says James. Seal it slowly while it's mainly submerged, and you're ready to go.
Check the TemperatureCulinary probe thermometers cost a few pounds but are important. They allow the cook to check the temperature of the middle of the fish or meat before serving, to ensure it has reached a safe temperature. A well-done steak, for example, should come up to 70°C. Those who like their steak rare, however, should stop it cooking once the centre reaches 54°C -- any lower and the temperature could veer from being hot enough to cook the meat, to being in the "danger zone" where bacteria multiply. Different foods have different base temperatures. The centre of chicken must reach 60°C, the centre of fish 40°C. Consult a guide, like the one at chefsteps.com.
Don't be afraid to go big"Most people start off with eggs, but for me it was steak, steak and more steak," says James. (The advantage of sous vide eggs is that they don't need vacuum bags – they cook in their shells.) If an egg doesn't seem worth the effort, start with hulking chunks of meat: "Fancy restaurants have been cooking steaks sous vide since the 70s," says James. "It's easy to create the perfect medium-rare steak with practically zero effort. Just season your steak, bag it, cook at 55°C for an hour, sear it in foaming butter in a hot pan and you've got something which is top-restaurant quality."
This article was originally published by WIRED UK
