07 March 2012

International Journal of Gastronomy and Food Science


It is the threshold we all want to breach. How can we make cocktails more than just a cocktail. How can we build them into an experience, one that stimulates, excites and engages all of our senses much like food has done.

With the advent of The Culinary Journal on Gastronomy and Food Science, help is on hand. It is often described as a cross between the Modern Cuisinist and a science paper, however still maintaining its accessibility to the curious yet unschooled scientist. The information provided is vast and considering we have only currently seen volume 1, we can expect this treasure chest to grow and grow with each new release. Perhaps most notable, is the fact that all of this knowledge is entirely free and available to download as pdf's!

A little about the journal

"International Journal of Gastronomy and Food Science is an English language, peer-reviewed publication in the area of Gastronomy and Food Science. The journal reviews and explores adopting a scientific approach to all the current facets of this growing field: applied culinary and food science, technology, new culinary concepts, nutrition, food service, global tendencies in food (health, globalisation, ethnic flavours, etc.) and the socio-cultural aspects of gastronomy."

Below are some of the most relevant excerpts from an essay on "Sous Vide Cooking: A Review". I tried to pick out sections that would translate most easily to bar work, so please do take the time to read the full journal and article. Although much of the content currently focuses on food and we might have to rethink a few dishes to get them fitting into a martini glass, the concepts and ideas we can take away and build on ourselves are still extremely valuable.

You can read and download the full article at - http://dx.doi.org/10.1016/j.ijgfs.2011.11.011

You can read and download the full journal at - Science Direct

Introduction

Sous vide is French for “under vacuum” and sous vide cooking is defined as “raw materials or raw materials with intermediate foods that are cooked under controlled conditions of temperature and time inside heat-stable vacuumized pouches” (Schellekens, 1996).

Food scientists have been actively studying sous vide processing since the 1990s (cf. [Mossel and Struijk, 1991], [Ohlsson, 1994] and [Schellekens, 1996]) and have mainly been interested in using sous vide cooking to extend the shelf-life of minimally processed foods—these efforts seem to have been successful since there have been no reports of sous vide food causing an outbreak in either the academic literature or outbreak databases (Peck et al., 2006). Chefs in some of the world's top restaurants have been using sous vide cooking since the 1970s but it was not until the mid-2000s that sous vide cooking became widely known (cf. [39] and [Roca and Brugués, 2005]); the late-2000s and early-2010s have seen a huge increase in the use of sous vide cooking in restaurants and homes (cf. [7], [Keller et al., 2008], [Blumenthal, 2008], [Achatz, 2008], [64], [Baldwin, 2010], [Potter, 2010], [Kamozawa and Talbot, 2010] and [Myhrvold et al., 2011]).

Sous vide cooking differs from traditional cooking methods in two fundamental ways: the raw food is vacuum-sealed in heat-stable, food-grade plastic pouches and the food is cooked using precisely controlled heating.

Vacuum-sealing has several benefits: it allows heat to be efficiently transferred from the water (or steam) to the food; it increases the food's shelf-life by eliminating the risk of recontamination during storage; it inhibits off-flavors from oxidation and prevents evaporative losses of flavor volatiles and moisture during cooking (Church and Parsons, 2000); and reduces aerobic bacterial growth—this results in especially flavorful and nutritious food ( [Church, 1998], [Creed, 1998], [García-Linares et al., 2004], [Ghazala et al., 1996], [Lassen et al., 2002], [Schellekens, 1996] and [Stea et al., 2006]).

Precise temperature control has more benefits for chefs than vacuumized packaging does: it allows almost-perfect reproducibility ( [Keller et al., 2008], [Blumenthal, 2008] and [Achatz, 2008]); it allows greater control over doneness than traditional cooking methods ( [7], [64], [Baldwin, 2010] and [Myhrvold et al., 2011]); food can be pasteurized and made safe at lower temperatures, so that it does not have to be cooked well-done to be safe ( [7] and [Baldwin, 2010]); and tough cuts of meat (which were traditionally braised to make them tender) can be made tender and still be a medium or a medium-rare doneness ( [7], [Baldwin, 2010] and [Myhrvold et al., 2011]).

This paper first reviews the importance of time and temperature in sous vide cooking in Section 2. Section 3 discusses the basic techniques of sous vide cooking. Food safety principles important for sous vide cooking are detailed in Section 4. Some conclusions are drawn in Section 5. Finally, Appendix A briefly discusses the mathematics of sous vide cooking.

Plants

While vegetables are a rich source of vitamins and minerals, boiled or steamed vegetables lose nutrients to their cooking water (Charley and Weaver, 1998). Sous vide cooked vegetables, in comparison, retain nearly all their nutritive value ( [Creed, 1995], [Schellekens, 1996] and [Stea et al., 2006]). This superior retention of nutrients also intensifies the flavor inherent in the vegetable and can cause some vegetables, such as turnips and rutabaga, to have a flavor that is too pronounced for some people (Baldwin, 2010).

Vegetables that are boiled, steamed, or microwaved lose their nutrients because the cell walls are damaged by heat and allow the water and nutrients in the cells to leach out (Charley and Weaver, 1998). Sous vide vegetables leave the cell walls mostly intact and make the vegetables tender by dissolving some of the cementing material that holds the cells together (cf. [Plat et al., 1988], [Greve et al., 1994], [Georget et al., 1998], [Kunzek et al., 1999] and [Sila et al., 2006]). In vegetables, this cementing material starts to dissolve around 82–85 °C/180–185 °F. This cementing material can be strengthened by pre-cooking, say at 50 °C/122 °F for 30 min ( [Ng and Waldron, 1997] and [Waldron et al., 1997]). Starchy vegetables can be cooked at the slightly lower temperature of 80 °C/175 °F because their texture is also changed by the gelatinization of the starch granules in their cells ( [García-Segovia et al., 2008] and [Baldwin, 2010]).

While fruits are often eaten raw, chefs sometimes cook apples and pears until they are tender. Tart (high acid) apples, such as Granny Smith, soften faster than sweet (low acid) apples, such as Gala or Fuji, because the acid lowers the temperature at which the cementing material dissolves (cf. Charley and Weaver, 1998).

Legumes (beans, peas, lentils) are cooked to gelatinize their starches, make their proteins more digestible, and to weaken the cementing material that holds their cells together so you can chew them; see, for instance, Charley and Weaver (1998). Legumes cooked sous vide do not need to be pre-soaked, because they can absorb the same amount of water in 50 min at 90 °C/195 °F as they would in 16 h at room temperature (Charley and Weaver, 1998). Moreover, since the legumes are cooked in their soaking water, their water-soluble vitamins and minerals are retained.

Since vegetables, fruits, and legumes are cooked at 80–90 °C/175–195 °F, their pouches may balloon and need to be held under the surface of the water (say, with a metal rack). The pouches balloon because the residual air left in the pouch after vacuum-sealing expands and because some of the moisture in the food is converted into water vapor.
For example, Baldwin (2010) suggests that non-starchy vegetables be cooked sous vide at 82–85 °C/180–185 °F for about three times as long as they would be boiled, starchy vegetables at 80 °C/175 °F for about twice as long as they would be boiled, and legumes at 90 °C/195 °F for 3–6 h, depending on the species and when it was harvested.

Conclusion

Sous vide cooking is a powerful tool in the modern kitchen: precise temperature control gives superior reproducibility, better control of doneness, reduction of pathogens to a safe level at lower temperatures, and more choice of texture than traditional cooking methods; vacuumized packaging improves heat flow, extends the shelf-life of the food by eliminating the risk of recontamination, reduces off-flavors from oxidation, and reduces the loss of nutrients to the cooking medium.

Precise temperature control lets you take advantage of both the fast and the slow changes when cooking: the fast changes, such as doneness, are mostly determined by the highest temperature that the food reaches; the slow changes typically take hours to days and let you make tough cuts of meat, which would usually be braised, tender while maintaining a medium-rare doneness. Precise temperature control also gives you the ability to pasteurize meat and poultry at lower temperatures than traditional cooking methods and so they no longer need to be cooked well-done to be safe.

Vacuumized packaging is important when extended shelf-life is required: the vacuumized pouch prevents recontamination of food during storage and allows for the efficient transfer of heat. Vacuumized packaging is not necessary when doing cook-hold sous vide cooking and many restaurants do not vacuum package the food and cook directly in a convection steam oven or in a temperature controlled bath of fat (e.g., oil or butter) or flavored broth (e.g., stock) if it will be served immediately.

No comments: