Freezing leftovers is a great idea in theory. It makes me feel like a savvy homesteader, able to provide for myself and my beagle by preserving a lasagna for two months. Until I go to thaw a single slice of lasagna and it’s stuck in a giant frozen cheese brick. That’s why I embrace flash freezing, or quickly freezing individual food portions before packing them away in airtight containers.
There are two different kinds of flash freezing: industrial flash freezing, or blast freezing, which involves freezing foods at cryogenic temperatures, sometimes with the help of a little liquid nitrogen. Industrial flash freezing helps prevents moisture loss in the food, which is why it’s regularly employed by frozen meal companies.
The second kind of flash freezing applies to the home cook. Flash freezing at home involves quickly freezing uncovered pieces of food, then packing the frozen portions into airtight containers.
Flash freezing is a great option for individual portions. Flash freezing is especially helpful for me, since I’m almost always cooking for one. If I’m making a large casserole—lasagna, for example—flash freezing allows me to thaw and use just one or two portions at a time, rather than thawing the whole casserole and letting food go to waste.
Flash freezing may help produce retain nutrients. Per the Mayo Clinic, flash-frozen produce may contain more nutrients than fresh produce. It sounds wild, but the flash-freezing actively stops produce from degrading, so the produce retains nutrients better. The Mayo Clinic cites Dr. Stephen Kopecky, a Mayo Clinic cardiologist. “We know once it’s picked a few weeks ago, it starts to decay and loses a lot of its nutrients,” Kopecky says in the article. “So studies have shown if you can flash-freeze something, it will retain its nutrients better because it retains its cellular integrity so the cells don’t get deformed.”
As a home cook, you can flash freeze pretty much anything. I’m talking individual cake slices. I’m talking berries. I’m talking muffins. I’m talking hamburger patties, cooked or uncooked.
To get started, just whip out a baking sheet or tray that fits in your freezer. Line the sheet with parchment paper or plastic wrap, then add the individual portions of food. Make sure to space the portions out—if the edges touch, the portions will fuse together as they freeze.
Freeze the portions, uncovered, for one to three hours or until the portions are firm to the touch. For tiny portions like individual berries, you can periodically check in to see if they’ve firmed up.
Finally, remove the food from the sheet and wrap it up tight—either in plastic wrap, resealable freezer bags, or freezer-safe food containers. You’ll have perfectly portioned foods ready to thaw at a moment’s notice.