Freezing and freezer burn: what ice does to food
Intermediate Kitchen science
Freezing turns food's water into ice, which pauses spoilage but can damage texture and dry out surfaces as freezer burn.
Written with AI help from the sources listed, and published by Cory. Spot a mistake? Tell us and we'll fix it.
How do you do it?
- Keep the freezer at 0°F or below, and do not pack it so full that air cannot circulate.
- Cool cooked food quickly in the fridge first, then freeze in shallow containers or flat bags.
- Press out as much air as you can, or wrap tightly in plastic and then foil.
- Freeze berries, cookie dough or meatballs spread on a tray, then bag them so they do not clump.
- Blanch most vegetables before freezing (from 1 minute for greens to several for dense ones like corn), then chill in ice water.
Why does it work?
When food freezes slowly, water forms large, jagged ice crystals that pierce cell walls; on thawing, the juice runs out and the food is mushy and wet. Fast freezing in thin layers makes smaller crystals and less damage. Freezing does not kill most bacteria; it only stops them growing, and they wake up again on thawing. Enzymes keep working slowly, which is why vegetables are blanched first. Freezer burn happens when ice on an exposed surface turns straight into vapor and escapes, leaving dry, grayish, tough patches that also pick up stale flavors. It is safe to eat, but trim it off for better taste.
What are the common mistakes?
- Freezing food in loose, airy bags — freezer burn within weeks.
- Refreezing thawed food over and over — more ice damage and mushier texture each time.
Still stuck? Watch someone do it on YouTube.
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