Watch cooking programs on television, from Top Chef to MasterChef, and it won’t take long for your ears to attune to the term sous-vide (French for “under vacuum”). This modernist cooking technique is ubiquitous, and is often the answer to the question: how does this restaurant prepare meat that’s so tender, moist and perfectly cooked?
First of all, what is sous-vide? Sous-vide is deceptively simple: an ingredient of your choice, usually a protein, is sealed in a vacuumed plastic packet and immersed in hot water that is kept at a constant, controlled temperature (here is a selection of sous-vide recipes to try). The result is an ingredient that is evenly cooked through and tender, from what might be hours of gentle heat (think of the tenderness of long-braised meat, but without the disintegrating texture).
It has always been a difficulty for cooks to prepare food that is evenly-cooked throughout, since heat is normally first applied to the outside (when your steak touches the hot pan) so, naturally, the outside cooks faster than the inside. Sous-vide solves this conundrum. You can slow-cook a protein, then quickly sear it, and it will look as though it were grilled, but have that sublime tenderness to the tooth. It feels like a magic trick to astonished restaurant guests and, to be sure, professional kitchens own powerful sous-vide machines that cost thousands. But recently, a number of small-scale, reasonably-priced sous-vide units for the home kitchen have come on the market. We decided to put them to the test. Can a home sous-vide machine reproduce the wonder of restaurant cooking?
AN OLD TECHNIQUE FOR A NEW METHOD
Though the method is newly avant-garde, the technique is old. It was first recorded by Sir Benjamin Thompson, Count Rumford, in 1799, who described heating food evenly via controlled-temperature steam, but the difficulty in maintaining a precise temperature for the steam or water meant that it was not adopted regularly until the 1960s, when the process was used for the industrial preservation of food. It is, essentially, a portion-by-portion twist on how canned foods are sealed: creating a vacuum inside them and immersing the entire cans in hot water. The first restaurant to use the technique to prepare meals was Restaurant Troisgros in Roanne, France. In 1974, chef Georges Pralus experimented with cooking foie gras in a way that retained its texture and appearance, without losing the delicious fats that bind it together. Chef Bruno Goussault is credited with introducing the technique to the United States, as he conducted research and taught courses as a scientist with Cuisine Solutions, in Virginia. Since the early 2000s, sous-vide has made its way into kitchens large and small, the basis for ventures into “molecular gastronomy.”
TESTING SOUS-VIDE AT HOME MACHINES
Most of the sous-vide at home machines on the market are available for $200-400. Not small change, but neither is it going to break the bank for a dedicated foodie. It also is an accessible price for small-scale restaurants, or even pop-up food trucks, which have neither the space nor the budget for the major league versions that can run $2000 and up. I decided to try out several machines that cost a maximum of $400, to compare their functionality, and to see if this technique really does transfer to the home kitchen. Most of the machines available (and there are not many, at least not yet) are the same size: a bit larger than a microwave oven—the size determines how large an ingredient you can cook inside it. This means that you need a kitchen with sufficient counter space to accommodate a machine that you might not use frequently. All of them operate on the same principle: they are, essentially, water heaters which allow you to choose a temperate via a digital touchscreen, and the water will rise to that temperature precisely, and remain there as long as you like. While buying a $400 water heater doesn’t sound particularly practical, the simplicity of the technique is difficult to achieve without it—imagine just putting a pot of water to boil and using a thermometer to check the temperature, then raising and lowering the heat to maintain it to the degree you are after…for days running (one cook tried to sous-vide meat for 96 hours!) This level of control allows you to play, and that’s really the point—this is not a tool for cooks who have no pretension to be home “chefs.” It is a gadget that should be used for fun experimentation. For instance, you can cook a filet of fish, sous-vide, in 18 minutes at temperatures ranging from 44c to 61c, as suggested in A Practical Guide to Sous Vide Cooking. But you could also cook it for much longer, just to see what happens.
SOUS-VIDE AND VACUUM SEALER
One factor that distinguishes the more expensive home sous-vide machines is whether they come with a built-in vacuum sealer. It should be noted that vacuum-sealing is not strictly required for the technique, nor is the plastic bag, but both offer a number of benefits. By mixing spices and ingredients (say, mustard and thyme) into a bag with the protein (say, pork chops) you intend to cook, the flavors meld nicely, increasing the chances for experimentation. The bag helps to keep the ingredients in place, as without the bag there is the danger that they might start to disintegrate in the water (delicate fish, for instance). And it helps with storage, as you can cook whatever you like, remove it still bagged, and pop it in the refrigerator. Bagging up the food with air in the bag can result in uneven cooking, and oxygen in contact with proteins will eventually turn them rancid, whereas they can last enormous lengths of time if the oxidation process is avoided via the vacuum. So you can, indeed, use a sous-vide machine without a vacuum-sealer. Having to buy a separate vacuum-sealer (they cost around $80 normally) feels like yet another single-use gadget to clog up the kitchen. But then, the sort of person who will enjoy using a sous-vide machine is probably the same person who can “go to town” with a vacuum-sealer, so perhaps it’s not really a negative?
My guess is that future kitchens will come with sous-vide at home machines, just as microwave ovens are standard now, but viewed as the cutting edge of weird kitchen gadgetry a few decades back. Whether you join the revolution now, or wait until it is a revolution for home cooks no longer and has become the norm, is really a question of how much space you have on your counters, and whether you are a gadget junky.
Geranium's Rasmus Kofoed has decided to stop serving meat at the restaurant currently ranked number two on the World's 50 Best Restaurants list. But the Danish chef isn't yet willing to go purely plant-based.