I know, I know: I'm about ten years late to the party on this one. Sous vide cooking techniques have become universal in the restaurant business, and probably half of the "foodies" in North America have a sous vide gadget sitting in a kitchen drawer somewhere. I'm a late adopter: I prefer to let other people get the bugs out of things before I take them up.
If you're even later to the party than I am, sous vide is a method of cooking which uses food vacuum-sealed in plastic bags (though you can do a perfectly adequate job of vacuum-sealing with a zip-lock bag and your lungs). The bag is then immersed in a water bath which is kept at a precise temperature. (The availability of cheap electronic thermostats in recent years moved it from high-tech cookery to something you can do at home.)
The process allows for very long, slow cooking of meats to exactly the desired level of done-ness. When meal time arrives, the meat can be quickly seared in a pan or flash-broiled to give it a proper Maillard-reaction exterior crust. You don't have to balance time and temperature to get the interior properly done without overcooking the outer layers.
One reason I was late to the party is that sous vide is always promoted as a way to cook steak. But since my preferred steak is essentially "beef sushi" I never saw the point. It's already done as much as I want inside; it comes that way straight from the cow.
Nevertheless, my tech-loving wife gave me a sous vide cooking device (it's a thermostat, an immersion heater, and a circulating pump, but there's no good name for the whole thing) for our anniversary. Events intervened this summer, so we only really got to start playing around with it in the past couple of weeks.
She used it to prepare a hanger steak, but neither of us could tell the difference between a "vided" hanger steak and a regular one. (See the remarks about "beef sushi" above.) I was starting to think it was all hype, but resolved to give it a fair test. So I bought a four-pound chuck roast, put it in a gallon ziplock back with a couple of minced garlic cloves, some salt and pepper, and some rosemary, then put it in the water bath at 135 Fahrenheit for six hours. Shortly before dinnertime I took it out of the bag and seared it, then cut slices.
I was expecting something like pot roast, but the interior was still quite pink. Effectively I had a four-pound steak on my hands. The long low-temperature soak had converted most of the connective tissue to gelatin so it was quite tender (though not "fork-tender" as one of the recipe sites I looked up claimed). The fat was mostly un-rendered, so it was wonderfully moist. (Indeed, after six hours of cooking there was no more than a couple of tablespoons of juice in the bag.) Delicious, really. I'd guess that among the three of us we must have put away a third of it — though I must point out that one of us is a growing fourteen-year-old.
We discussed other things to cook in the same way. Vegetables don't seem to be high on anyone's sous vide list, if only because you really do have to get close to boiling to make most of them tender, and long low-temperature cooking doesn't really do much for the flavor. It would also be tricky for any stew-like dishes (boeuf bourguignon, ragout, curry, etc.) since they also contain vegetables. Although it would be great for keeping a pre-cooked dish like that ready at serving temperature . . . which of course is what many restaurants do nowadays.
It seems that it's better to think of sous vide not as a cooking method but as a pre-cooking technique, analogous to marinating. Use it to prepare the meat before you actually cook it. I've got some ideas I'd like to try: cooking a leg of lamb in the water bath all day and then finishing on the grill with some aromatic woods, or possibly a pork loin. I'm very nervous about using this method for poultry, however. It may take me a while to work up the nerve to try that.
So, the final verdict: cooking meat sous vide works very well. I'll be doing it again.
For stories involving beings made of meat, buy my new ebook, Monster Island Tales!