“How does a cryovac affect food storage in the cooler? Does it extend the life of raw and cooked food? Does it shorten the life of either? I know it prevents freezer burn.”
“Cryovac” is food-industry shorthand for “vacuum-pack”—meaning to wrap foods in impermeable plastic, then remove most of the air inside the package to prevent oxidation (causing rancidity or darkening in color) and inhibit the growth of most pathogens—both important factors in a food’s decay, or spoilage. Today, there are a number of companies that produce vacuum-packaging supplies, but the process was perfected in the 1950s by a South Carolina business called Cryovac, Inc. The folks there created a tough, flexible heat-shrink bag for freshly slaughtered turkeys—in effect, turning a Thanksgiving or Christmas delicacy into something that, if frozen, could be shipped longer distances and enjoyed all year long.
Better-protected foods means less spoilage—thus reduced food costs—and loss. According to the EPA, more food reaches landfills and incinerators than any other single material in municipal solid waste. In 2010, more than 34 million tons of food waste was generated. “The key thing about oxygen-barrier packaging is that it helps prevent food waste,” said Rick Watson, Cryovac bags product director for North America. The company, now a division of the Fortune 500 company Sealed Air, makes a couple of billion units a year, he added. They do not contain bisphenol A (BPA).
Vacuum packaging is not a substitution for refrigerator or freezer storage of meat and other foods—whether raw or cooked—that require cold storage. But compared to how most meat, for instance, is sold at the supermarket—covered with thin, permeable plastic wrap—vacuum packaging gives it a longer shelf life in the fridge or freezer. In fact, it’s virtually impossible for a vacuum-packed food to develop freezer burn—what food-chemistry authority Harold McGee explains in On Food and Cooking as the “slow, patchy drying out caused by the evaporation of frozen water molecules directly into vapor.” If you’ve ever had a freezer-burned steak, which tastes stale and is cottony and tough, you’ll know how flavor and texture suffer.
These days, you’ll find vacuum packaging used on everything from blocks of cheese and deli meats to coffee (whole beans and ground), rice and whole grains, grass-fed beef, pastured heritage pork, even precooked baby beets. In fact, it’s difficult to imagine the growth of the food industry without it—or the au courant culinary technique called sous vide (French for “under vacuum”), in which foods are vacuum-sealed in a plastic pouch, then cooked in a hot-water bath for a long time at a very precise low temperature. (Curious? Post a question and I’ll give you the scoop.)
And let’s not forget about the recent resurgence of interest in home preservation, aided and abetted by vacuum-packaging equipment geared for home use. In our still-troubled economy, people are buying food in lower-cost bulk quantities, repackaging it in smaller portions, and stashing it in the freezer to stretch their food dollars—but there’s more to it than that. Many home cooks are interested in growing their own food so they know exactly what they’re eating—or feeding their family. Or, if they’re committed to eating locally, preserving summer’s bounty helps get them through the winter months, when seasonal offerings (potatoes, parsnips, rutabagas, repeat) are far more limited.
Me? I leap into action when sour cherries come into their all-too-brief season. I buy pounds and pounds of them at the Union Square Greenmarket and pit them over a bowl to catch the juices (they’re so soft, you don’t need a cherry pitter; just use your fingers to gently squeeze the pits out through the stem ends). I freeze some of them with the juices for preserves or sauces. The others I keep whole, for cherry pies. The best way to deal with whole cherries (or berries), by the way, is to spread them on a paper towel–lined rimmed baking sheet and freeze them; when they are frozen solid, bag them and refreeze.
I don’t have the time, budget, space, or patience to test the wide array of home vacuum sealers available, but if you have a favorite, let us all know. Recently, I pitched out my Reynolds Handi-Vac Vacuum Sealer (available at supermarkets for around $20, but a royal pain to use and not terribly effective) and am planning to order a FoodSaver V2244 (available online for around $80), a Cook’s Illlustrated “best buy” back in 2009 and still recommended by friends. Can’t wait for cherry season.
Food safety note: I’d be remiss if I didn’t mention that there are precautions you must take when vacuum-packaging foods at home. A number of county extension offices reference the National Center for Home Food Preservation, at the University of Georgia.
There’s a handy tip sheet from the El Dorado County branch of Master Food Preservers, University of California Cooperative Extension (UCCE).