What is freezer burn, and can it be prevented?

Freezer burn is the dry, dull-colored patch that forms as the water on the surface of a product leaves it over time. This is not microbiological spoilage but a loss of moisture; the result is a loss of flavor and texture. Packaging that keeps air out and a freezer temperature that does not swing delay it noticeably.

What exactly are those white patches?

In a frozen product the water is in the form of ice crystals. If air is left inside the package, over time these crystals leave the surface of the product and collect as frost on the inner surface of the package. What is left on the product side is a dry, porous, faded surface; although it is called burn, there is no heat involved, only drying.

This is why you see the patch most on the surfaces facing the empty part of the package: the corner of the meat that does not touch the bag, the gap between the lid of the container and the food, the fold near the mouth of the bag.

Because the drying starts at the surface, the shape of the product changes the result too. A thin, wide slice carries far more surface than a thick piece of the same weight; so thinly cut meat and small pieces frozen individually show the patch earlier.

Why does the packaging matter this much?

The Turkish Food Codex communiqué on quick-frozen foods (Hızlı Dondurulmuş Gıdalar Tebliği) requires that products offered to the final consumer be packaged so as to be protected not only from contaminants but from moisture loss as well. In other words, holding moisture is one of the two jobs the regulation assigns to the packaging; not decoration, but function.

TÜBER, Türkiye's national dietary guideline, points to the same place for home freezing: even if the food will be eaten soon, it should be packaged so that no air gets through. Frozen products should be kept in their own original packaging; packaged foods should be stacked tightly and flat. A flat package does not only save space, it leaves less air inside.

What does a swinging temperature speed up?

The communiqué requires the temperature at every point of the product to be held at -18 °C or lower and kept there; it also limits the tolerance for the short rises that can occur in transport, distribution and retail cabinets to 3 °C. A freezer at home is not monitored to that degree, but the logic is the same: the more often the temperature swings, the more chances the water at the surface gets to move.

The door being left open for a long time, a hot container being put straight inside, and the freezer being packed so full that the air cannot circulate are three ordinary situations that widen that swing. All three repeat unnoticed in daily use.

Do you eat it or throw it out?

A burned surface is a sign of drying, not a sign of spoilage. What to look at when judging the product is not the patch itself but when that package was frozen and whether its packaging is still intact. This is exactly why the guideline says to write the type of food and the date of freezing on food frozen at home; without a date there is no answer to the question of how long it has been sitting.

If the dried part bothers you, cutting it away before cooking is a more measured decision than getting rid of the whole product. If the burned surface is large and the package has been sitting for a long time, make the decision by looking at the time, not at the patch.

Where things sit inside the freezer affects this decision too. The area closest to the door meets outside air every time it opens; putting packages that will stay a long time at the back and the ones you reach for often at the front reduces the effect of the temperature swing.

What can you do today?

Push the air out as you pack: before closing the mouth of the bag, flatten it with your hand to empty the air inside, and in containers do not leave a large gap above the food. Divide it into meal-sized portions; every time you open a large package you introduce the rest to air again. Write the type and the date on every package, and use the oldest one first.