Glossary
Freezer burn
Dry, grayish-white patches on frozen food caused by air exposure, usually from a poor seal.
Freezer burn appears as dry, discolored patches on the surface of frozen food, caused by moisture escaping from the food and being replaced by air inside the packaging. It is not a safety hazard, but it dries out and toughens the affected area and can give reheated meals an off, freezer-y taste.
The main prevention is minimizing the air around the food, which is why vacuum sealing works so well for longer freezer storage. Airtight freezer containers and freezer bags with the air pressed out before sealing also help, along with freezing food flat and cooling it fully before it goes into the freezer, since trapped warm air adds extra moisture that later turns to frost.
A common mistake is reusing containers or bags that no longer seal tightly, or overfilling the freezer so items get pushed around and packaging tears. If you do see freezer burn, the affected portion is usually safe to eat once trimmed away, but the texture will stay tougher and drier than the rest of the meal, so it is worth eating the oldest freezer meals first rather than losing more of them to burn over time.