The precise control of temperature and time determines the quality of culinary preparations
Sous vide cooking differs from traditional culinary methods in two key aspects: first, raw food is placed in a heat-resistant bag in total or partial absence of air; next, it is cooked for a determined time and at a lower than usual, totally controlled and constant temperature. The process is usually carried out in a thermostatically controlled water bath, or “roner” (a name derived from the instrument’s designers, chefs Joan Roca and Narcís Caner). Although a steam oven with temperature control also works, the roner allows for more consistent cooking.
The introduction of food into a bag where air is extracted has been applied for a long time. However, it was used only as a preservation technique for coffee, fruits, vegetables, and cooked products. The absence of air prevents oxidation reactions, which prolongs the shelf life of the food.
The first application of vacuum to cooking dates back to 1974, when Georges Pralus used it to prepare a duck liver terrine. But the expansion of this culinary method was marked by the publication, in 2003, of “Sous Vide Cooking,” a book by Joan Roca and Salvador Brugués that delved into technical details and recipes. Bruno Goussault and Thomas Keller also contributed to its dissemination.
Sous vide cooking offers several advantages. Cooking in a bag and extracting air ensures the preservation of the organoleptic qualities of the food, as it prevents the evaporation of volatile substances and the loss of internal juices. It also avoids the oxidation of sensitive foods (apple, artichoke) and reduces the proliferation of aerobic microorganisms.
The control of temperature and time allows for each food to be cooked to its exact point. If chicken thighs usually come out juicy and tender, and the breast dry and stringy, it is because the same temperature and cooking time are applied to both parts, when they require different cooking: the breast should be cooked at a lower temperature and for less time to retain its juice.
However, the method also has drawbacks. As the working temperature is lower, the risk of bacterial presence increases. Short cookings below 65 ºC involve some microbiological risk; pasteurization does not occur, so the dish must be served immediately (“direct cooking”). Long cookings above 65 ºC can be stored in the fridge for a reasonable time, as they are considered pasteurized products (“indirect cooking”).
Another downside is the toxic bacteria Clostridium botulinum, which reproduces in oxygen-free (anoxic) environments. Its spores are difficult to eliminate, even at high temperatures; their multiplication is avoided only at temperatures below 3.3 ºC.
To cook vegetables, we usually resort to boiling, which takes away their color and flavor, or the oven, which dries them out. If we apply sous vide cooking, we must take into account that at 85 ºC, fiber hydrolysis occurs; between 80 and 85 ºC, starch and cell walls soften. Vegetables are usually cooked at 85 ºC; the time will depend on the proportion of fibers and starches. Zucchini, which contains 0.82 grams of water-insoluble dietary fiber per 100 grams of product, requires about 20 minutes of cooking; carrots, with a higher fiber content (1.889 grams per 100 grams of product), 40 minutes.
In meats and fish, cooking conditions are determined by proteins. Fish proteins exert a lower cohesive force than meat proteins; their cooking occurs from 45 ºC, and with it, the release of fluids contained in muscle fibers, whose main component is myosin. The ideal cooking temperature for fish is low: between 50 and 60 ºC.
In meats, collagen’s strength requires higher temperatures and longer cooking times. In general, bath temperatures around 65 ºC are recommended. Tough meats require longer times; tender ones, shorter. We will cook a chicken breast at 60 ºC for 20 minutes, reaching 62 ºC at the core; the microbiological risk will require us to serve it immediately. At the same bath temperature, pork ribs will require 24 hours of cooking; with pasteurization, they can be stored in the fridge for a reasonable time.
Current and future cooking cannot be conceived without sous vide cooking. The next step: its entry into homes.
