Saturday, I went to put the leftover roast chicken bones into the stock bone bag in the freezer and found it full. Time to make stock! Pulling out one of the bones, a bit of seven bone chuck, I thought back to that meal. That was my first try at using a new technique, home sous vide in a camping cooler, and it had turned out great!
I'd used the technique with great success several times after that, during the recent Bay Area heat wave it proved an invaluable method of moving heat out of the kitchen. But I'd been wondering a few things about the safety of the technique so I did a bit of research. I'll explain what the sous vide technique is, how it works, and what equipment a home cook would need to use it. I'll also address the food safety and environmental concerns I've had with sous vide.
Sous vide is French for "under vacuum." Most people who know what it is think of it as cooking food in bags using a constant temperature water bath. Technically, it refers to any food prepared using a vacuum, not necessarily cooked at all. Using vacuum to compress fruit such as watermelon is one example. I will be discussing cooked sous vide, as I don't even own a vacuum sealer, which is necessary to get the compression required for fruit.
While you can buy a half pan sized water bath unit for around three hundred dollars, and a cheap vacuum sealer for fifty, you don't need either of these things to try sous vide. One can get most of the air out of a gallon freezer bag simply by submersing it up to the top in water. Rather than using a recirculating water bath to maintain a constant temperature, you can do a good enough job with a camping or beer cooler to cook meats this way.
Sous vide cooking works its magic two ways. First, it concentrates flavor, keeping all the food's natural liquids and flavors in the food. Second, it gently raises the temperature of foods and keeps them in the range that will produce exactly the chemical activity desired by the cook. A steak can be cooked to a perfect medium rare, all the way from edge to center. Fish can be cooked to the exact point that it becomes firm without becoming dry. Vegetables can be cooked to the point that pectin starts to break down, and no further.
The one type of activity sous vide can not produce directly is browning. However, by raising the internal temperature of the food, it promotes quick and easy browning later. Just dry the food and throw it in a hot skillet or on the grill for thirty seconds per side and watch it develop a thick dark sear almost instantly.
Chefs use sous vide to cook all sorts of things, and if you spend around three hundred fifty dollars, you can do anything they can do with the technique. The beer cooler technique is suited to meat and not much else, but that is enough. One taste of meat cooked this way and you'll agree.
Some of you may be wondering about food safety, after all, a steak reaches medium rare at 125 degrees Fahrenheit, which is within the food safety danger zone. Will sous vide necessarily kill all bacteria present on a cut of meat. No! Most food should be safe if raised to over 140 F for over thirty minutes, trichonosis is pork notwithstanding. But just to be safe, meat cooked sous vide should be finished in a pan or over a grill, to kill of any surface bacteria. More in depth food safety guidelines can be found here.
Others may be wondering, as I did, about the safety of the bags used, won't they leach bad chemicals into the food? Others may be concerned about the waste, all those plastic bags being thrown out. I was concerned about both, and found the answer in this informative blog post. Spoiler alert: reusable food grade silicone bags are the answer to both problems. But at twenty dollars a pop, I would advise people to try the technique first before buying the good reusable bags that won't give you breast cancer.
If you are interesting in giving this fun and easy cooking technique a try, I advise reading the beer cooler guide I linked to above. He explains it better than I could. Or just throw some steaks and whatever seasonings you like in a freezer bag, get the air out by holding it part way underwater, throw the bags and some 140 degree water (you do like your steaks medium rare, don't you?) into a beer cooler for forty five minutes, then take them out and sear them for thirty seconds a side. You will be a convert!