Sous-vide ("sue Veed") is French for "under vacuum." Traditional oven cooking methods use dry heat that demands precise control of timing to avoid overcooking. A medium-rare roast that requires an internal temperature 134°F is often cooked at an oven temperature of 350°F. The sous-vide method uses a water oven to eliminate this temperature disparity. Food is sealed in a plastic food-safe bag and immersed in water. A temperature controller circulates the hot water. It moderates and controls heat precisely and allows great latitude in cooking times, since the food cannot be overcooked or burned. Foods release moisture and juices, but these are captured in the bag and not evaporated. The Maillard reaction for browning meat is accomplished separately with a grill, torch, or searing hot iron skillet.
How long does food need to be held in the water oven? It largely depends on thickness. Here's a handy reference for cooking times.
My sous-vide cooker is the Sansaire.
Find reviews of other devices at Serious Eats and comparative benchmarks at Jason Logsdon's site. At this writing (2016) there are a number of very cheap sous-vide circulators being rushed to online stores, often accompanied by fabricated reviews. "Cheap" is not what you want. Instead look for temperature accuracy, easy-to-clean (in case a food bag leaks), and features that make the device a pleasure to use.
The Water Oven benefits from a lid, which greatly reduces evaporation. I cut the corner off to make room for the sous-vide device. You can also do sous-vide cooking on the cheap in a beer cooler.
A vacuum sealer is helpful. This is the one I have: the Waring Pistol Vac. In early 2017, at the tender age of 2½ it died suddenly. Happily, the manufacturer replaced it at no charge. It uses its own specialty bags, which despite the claims are not reusable. I find 1-Qt and 1-Gal bags handle most everything well.
You can also seal Ziploc plastic freezer bags with the Archimedes method (useful if you need to seal liquids). The freezer bags are sturdy and not prone to leak.
Some foods have irregular shapes and air pockets may remain in the bag. Some foods, like brussels sprouts, emit gas when they are cooked. Sometimes the food bag will float. A trivet can be set on top of the bag to hold it down. You can use a binder clip to attach the top of the sous-vide bag to the top of the water oven. Secured this way, you can open the top of the bag a little bit and allow the gas to escape. But there should be a note of caution here. Do not allow the bag to leak food into the water oven, or you will find yourself needing to disassemble the sous-vide circulator in order to clean it. This is even less fun than it sounds like!
Seasoning is a little different with sous-vide cooking. Dried herbs are often better than fresh. After cooking meats sous-vide, wash off any remaining herbs and dry the meat thoroughly before searing.
Sous-vide can play well with smoking. A pork butt, cooked sous-vide at 160°F for 24 hours, releases a lot of liquid. This liquid is captured in the sous-vide bag. You can boil down the reserved liquid to reduce it by half. Rub the cooked pork butt and short-smoke it just long enough to make the bark, about 2-3 hours. When you pull the pork, add back some or all of the reserved liquid and you'll have amazingly juicy and flavorful pork!
Good Links Worth Exploring:
Writers, Stars, and Luminaries:
J. Kenji López-Alt
What's Missing? The Maillard Reaction.
Achieving Maillard: the science, a searing torch, another torch that uses a specialized searing head. Or just use your gas grill for a couple of minutes on the highest setting. Or a ripping hot cast iron skillet!
Get started with amazing corn-on-the-cob. Strip the husks and silks. Seal each ear in its own bag with one tablespoon salted butter. Cook sous-vide at 182°F for 20 minutes. You will never boil corn again!
I'm Ray Paseur, an occasional chef
p: 703.346.0600 (message OK)