Equipment & Vessel Techniques

Vacuum Sealing / Cryovac

Also: vacuum packing, cryovac, cryogenic vacuum, vac-seal, vacuum packaging

Removing air from a sealed bag around food to extend shelf life, enable sous vide cooking, or accelerate marinade penetration by exploiting pressure differential across cell membranes.

The Cryovac process was patented by W.R. Grace & Co. in the 1940s and commercialised for meat processing. 'Cryovac' as a generic term for vacuum-packed fresh protein entered English restaurant kitchen vocabulary by the 1970s. Sous vide use of vacuum sealing was formalised by Georges Pralus and Bruno Goussault in the 1970s–80s.

Definition

Vacuum sealing is the process of evacuating atmospheric air from a food-grade bag (typically polyethylene or nylon/polyethylene laminate) before heat-sealing it shut. Two primary systems are used in professional and home kitchens: edge sealers (suction is applied through a channel in the sealing bar — common in home settings) and chamber vacuum sealers (the entire bag is placed inside a pressurised chamber that drops below atmospheric pressure, then reseals — the professional standard). Chamber sealers are required for liquids and high-moisture foods because the suction in edge sealers draws moisture into the machine. The term 'Cryovac' is a brand name (from the Sealed Air Corporation) that became genericised in foodservice to describe any commercial vacuum-packaged product. Vacuum sealing serves three distinct culinary functions: (1) Preservation — removing oxygen slows aerobic microbial growth and lipid oxidation, extending refrigerator life by 2–5× and enabling wet-ageing of beef. (2) Sous vide cooking — the sealed bag allows precise thermal transfer in a water bath, and the inert sealed environment eliminates evaporative loss. (3) Rapid marination — when the vacuum pressure is released after pulling a partial vacuum, atmospheric pressure drives marinade rapidly into the opened cellular spaces of the food, achieving in 30 minutes what conventional marination requires hours to accomplish. This 'compression marinating' also works with delicate fruits: sealing cucumber or watermelon under vacuum collapses air pockets, densifying the texture and intensifying flavour in a technique popularised by modernist cuisine. Vacuum sealing does not sterilise — anaerobic pathogens (particularly Clostridium botulinum) can still proliferate in the low-oxygen environment, making temperature discipline critical for any vacuum-sealed food below pasteurisation temperature.

In use

“The chef vacuum-sealed the duck legs with thyme and orange zest, then placed them directly into the 68 °C bath for twelve hours — Cryovac and sous vide inseparable in this kitchen.”

Related terms

Sous VideChamber SealerWet AgeingCompressionMAP (Modified Atmosphere Packaging)Cold Chain

References

1.Modernist Cuisine: The Art and Science of Cooking — Nathan Myhrvold et al. (The Cooking Lab, 2011)
2.Under Pressure: Cooking Sous Vide — Thomas Keller (Artisan, 2008)
3.On Food and Cooking — Harold McGee (Scribner, 2004)

Confidence: high

Notes

Chamber vs. edge sealer

For professional use, a chamber sealer is not optional — edge sealers cannot seal soups, marinades, or any liquid-containing bag without drawing the liquid into the mechanism. Chamber sealers also apply a more uniform, controlled vacuum level (expressed as a percentage or mbar), allowing the cook to dial in partial vacuums for delicate items like fish that would be crushed at full vacuum.

Botulism risk

Vacuum-sealing creates an anaerobic environment in which Clostridium botulinum can grow if temperature conditions are permissive. Any vacuum-sealed food held below 54.4 °C (130 °F) and above 3.3 °C (38 °F) must be kept for less than 4 hours in professional HACCP protocol, or rapidly chilled below 3.3 °C for extended holds. Garlic-in-oil sealed under vacuum is a documented botulism vector — acidify or freeze.

Compression in modernist technique

Chefs at El Bulli and The Fat Duck used full-chamber vacuum to 'compress' fruits: a watermelon cube sealed at 99.9% vacuum collapses its gas-filled cells so the cube becomes translucent, dense, and intensely flavoured — a texture that no conventional preparation can produce. This technique requires a chamber sealer and is one of the few genuinely novel culinary applications enabled by the equipment itself.