What Is Freezer Burn? Ask Paul

That’s the hope, at least. In practice, freezers are not perfect suspended-animation chambers.

Freezer burn is the general term for the unpleasant flavor, texture, and appearance that food can develop when frozen.

Inside a freezer, the air is very dry, because cold air can’t hold as much moisture as warmer air. The dryness of the air means that water evaporates more readily. This is the principle behind freeze-drying, and it’s the reason that, if you leave them untouched in the freezer too long, ice cubes shrink.

Even in frozen food, there is a small amount of liquid water and, if those molecules of liquid water are given the chance, they will evaporate. As that continues to happen over time, the surface of the food forms dried-out, burnt-looking spots. Flavor compounds also evaporate, even more quickly than water, leaving behind odd- or off-tasting food. And exposure to oxygen lets the surfaces discolor in unappealing ways.

With proper storage, food can stay burn-free for a year or more; but with improper storage, the damage—too warm or variable a temperature or poor wrapping—begins to set in within a day or two. 

Cold, dry air is the enemy. So putting food in a container in the freezer is a start, since that limits the amount of air that can reach the surface of the food.

Unfortunately, there’s still cold, dry air inside even a snug zipper-lock freezer bag or plastic container, and that air is enough to allow water to evaporate out of the food and then settle back onto the surface of the food as ever-growing crystals of frost. How can we keep the freezer burn at bay?

• Vacuum-sealing removes virtually all of the air from a plastic pouch, preserving an airtight environment in which food stays good much, much longer in the freezer.
• Wrapping food tightly in plastic wrap is not as effective as vac-sealing, but it prolongs the life of the food. In the case of ice cream or other food in a rigid container, you can press a sheet of plastic inside the container, flush against the surface of the food, to block air.
• Keep it cold. A freezer should be no warmer than 0°F (check yours), but if it's colder than that, it's even more effective. The colder the environment, the fewer of those molecules of water are liquid and hence prone to evaporation. Keep vulnerable foods as far from the freezer door as possible so that their temperature doesn’t fluctuate when it opens. If you have empty space in your freezer, consider occupying it with frozen bottles of water, which will help keep the temperature down.
• Date your packages of frozen food and eat them before they become antiquated and flavorless.

Yes, it won’t harm you; the frigid environment keeps microbes from spoiling food in dangerous ways. It just tastes bad.

Thawing the food and then removing the freezer-burnt portion will work in a pinch, depending on how deep the burn goes.