What is flash freezing?

Ever tried to freeze leftovers only to end up with a frozen mass that thawed into an unappetizing mess? Let us introduce you to flash freezing. In the food industry, this refers to the use of ultra-low temperatures to freeze food fast. But for those of us at home, it's a way to freeze single pieces — as in berries — or servings of food before packing them together for the longer term in the freezer. Flash freezing at home involves some forethought, preparation and time, but it's worth it.

Many of us are accustomed to throwing leftover meat, bread, cakes and cookies into a freezer container and hoping for the best. Sometimes it works out, but sometimes you end up trying to pry apart frozen chicken breasts with a butter knife. Flash freezing lets you thaw and reheat individual servings instead of entire containers of food.

If there's a bunch of leftover berries nearing the end of their refrigerator life, putting them in a freezer bag as-is will cause them to fuse into one frozen lump. This will be not so helpful later, when you'd like a handful to put in a smoothie. With flash freezing, you spread them out on a baking sheet or tray, then freeze them for a short time. This isn't a long-term freezing solution — the berries are uncovered, and the trays would crowd up your freezer. When the berries' surfaces have hardened, you transfer them to a freezer bag or another container. When you're ready for a smoothie, it's easy to grab just a few.

Flash freezing doesn't work for everything. Pouring individual portions of soup on a baking tray, for example, sounds like a bad idea. And most produce, unlike berries, should be at least partly cooked or packed in liquid before it's frozen. But flash freezing can be helpful for any raw or cooked food you can cut or break that would otherwise freeze into a too-big lump: meatballs, cookies, slices of pie, burgers, leftover lasagna, you name it.