We've shown you how to get started with sous-vide cooking before, but this video and guide from The Food Lab's J Kenji Lopez-Alt shows you how to get a perfect medium rare steak by cooking it in a beer cooler. When you're finished, you'll have a steak with a crust on the outside and perfectly medium-rare from edge to edge.
The "steak in a beer cooler" technique isn't new in itself; Kenji explained how to do it at Serious Eats back in 2010, and our primer to sous-vide cooking followed that example closely. Still, it can be tricky to get right, and Kenji walks you through the process in the video above.
If you have the money or the desire to pick up a real water oven, like the $300+ Sous Vide Supreme, it can take some of the guesswork out of this for you, and it will maintain your water temperature. But the beautiful thing about using a beer cooler is that it's insulated enough to hold your water temperature for a few hours.
As long as you get the water to the right temperature first -- by adding either boiling (to bring it up) or cold (to bring it down) water to a large volume of it -- you can cook a few steaks and hold them at the perfect temperature for hours before serving. Once your steak is at the right temperature, you can sear it in a hot skillet for a couple of seconds to get that delicious crust on the outside -- just don't sear it too long or you risk overcooking the interior. Hit the link below for Kenji's full guide.
How to Cook Your Steak Sous Vide in a Cooler [Serious Eats]