Your freezer is a molecular science lab in action. As it's doing its thing on your fruits, vegetables, and meats, it may also be affecting their size, taste, and texture. Follow these steps to keep their virtues intact.
Fast-freezing creates small ice crystals, while slower freezing produces large crystals," explains Lynne McLandsborough, Ph.D., an associate professor of food science at the University of Massachusetts-Amherst. In general, the smaller the ice crystal, the better the quality of the frozen food in terms of texture and water loss. The best way to freeze things quickly is to ensure you do it in a very cold (0 degrees F) freezer that isn't overpacked so that the frosty air can circulate, and in containers that have been packed to the brim. (Think of this as the home version of the food industry's flash-freezing, which exposes foods to seconds of cryogenic -- or crazy-low -- temperatures.) The larger the crystals, the more dehydration that's apt to occur, since a larger amount of water would need to migrate from the inside cells to create them. The thawed food, having dripped off more of its moisture, will be drier and may also have been affected in terms of its sweetness and saltiness.
Baby, It's Cold Inside
Dressing appropriately for a chill holds true for your food as much as it does for you. The best way to avoid freezer burn, which isn't dangerous but does cause cell-structure breakdown, thus affecting flavor and texture, is proper prepping.
Meat, poultry, bread, hard cheese, and fish can be tightly swaddled in butcher paper (waxy side in) and then in plastic wrap or aluminum foil. "This will ensure you don't get freezer burn by exposing the food to air," says H. Douglas Goff, Ph.D., professor of food science at the University of Guelph in Ontario, Canada. Small fish such as smelts can be frozen in water, which will help prevent dehydration.
Briefly boiling or steaming produce kills surface bacteria and deactivates the plant enzymes that can cause changes in flavor, texture, and color, explains McLandsborough. Limiting enzyme activity and deterioration also helps with vitamin retention. (For specific blanching times -- which vary vastly by vegetable -- visit the National Center for Home Food Preservation at nchfp.uga.edu.)
To freeze berries and other fruits, place them on a cookie sheet in a single layer and freeze until hard, then transfer to a container. A little sprinkling of sugar (raw, brown, or white) or of honey can help the water freeze in the tissue without causing too much cellular damage, says Goff. Berries are best frozen right away; other fruits should be left to ripen first.
When freezing prepared foods like lasagna or chili, layer, spoon, or pour them in right up to the top of the container. Leaving very little space, or "headroom," as it's known, prevents dehydration and oxidation, Goff says. If you freeze the food in the container it's going to be cooked in, it can often go right from the freezer to the oven.
Cool prepared foods before placing them in the freezer, since still-warm dishes can raise freezer temperatures and tend not to freeze uniformly. For fast cooling, add a few ice cubes to soups and stews, or place hot leftovers in a vessel set in a bowl filled with ice water. Divvying food into smaller containers can also help.