How to tell if food has freezer burn

Freezer burn typically strikes food that’s been frozen for a long time, let’s say many months or even years, or that’s frozen in a way that invites lots of moisture-sucking air to circulate across the surface of the food. When food is freezer burnt, water in the food does something vaguely magical called sublimation. In sublimation, water frozen within the food busts out as water vapor, skipping the whole liquid water phase entirely. (This is where I can’t help but imagine a movie where a ghost rises from someone’s body.) So, the food loses moisture, which can mess with its flavor and texture. 

Sublimation occurs in freezers because the air is naturally very dry (cold air can’t hold much moisture). With enough time, the dry air will suck moisture from things, like food, that contain water. Hence freezer burn. It’s basically dehydration, just with a below-freezing spin. This is also why ice cubes left for too long will shrink in their trays.

What freezer burn looks like

Freezer burn’s signature is light, often whitish, discolored patches. The white spots on the frozen vegetables in the image at the top of this post? That’s probably freezer burn. On produce, meats and other foods that contain intact cells; this means that water has been pulled out of cells, creating ruptures and disruptions that irreversibly damage flavor and texture. The food could also look shriveled and leathery.

If you’re only seeing ice crystals and can scrape them off, leaving food that looks relatively normal (for frozen food, at least), you probably are not dealing with freezer burn.

“Freezer burn presents itself as more powdery, but counterintuitively cannot be just brushed off,” explained Sanjay Gummalla, senior vice president for scientific affairs at the American Frozen Food Institute. The light patches, he said are “not just a coating, it’s the tissue and its structural damage.”

Can you undo freezer burn?

Generally, no. Proteins are particularly susceptible to quality losses from freezer burn because they “rely on their moisture content for texture and tenderness,” Gummalla explained. “Even modest moisture loss from freezer burn significantly degrades quality.”

Dehydration, like that wrought by freezer burn, can cause proteins to denature, so the meat will be less tender when it’s cooked, according to an article in the Washington Post. These changes are happening at the cellular level and can’t be undone.

But even in a high moisture food where cellular structure matters less (say, apple sauce) and where you could even add some water back during cooking, freezer burn can still permanently alter the food.

“Some of the textural changes resulting from freezer burn can be reversed,” Gummalla told me. “However, any flavor, color, and nutrition impacts are going to come through even after cooking. I, for example, can taste freezer burn (cooked or not, solid food or not).”

Another potential longterm storage issue you can’t undo is rancidity, which can develop invisibly alongside freezer burn as a food ages. Rancidity, in which oils break down and produce off flavors and odors, happens faster at room temperature, but will still eventually impart a chemically or cardboardy flavor to foods with oil or fat content that linger in the freezer for too long. So, freezer burnt or not, long-frozen fatty foods might still taste weird if rancidity has taken hold.

How to avoid freezer burn

Here are steps to avoid freezer burnt food:

• Tightly seal the food. Tight seals make it harder for the dry freezer air to pull moisture from the food. (But do allow head space for water expansion in rigid containers; otherwise your container might crack.)
• Keep your fridge around 0 degrees Fahrenheit. While anything below 32 degrees is technically “freezing” and is too cold for microbial spoilage, freezers that hover in the teens and 20s won’t preserve food as well as those at 0 degrees. This is because, Gummalla explained, even though water freezes at 32 degrees, frozen water molecules at 25 degrees have more energy and are more likely to be pulled away from the food by the freezer’s dry air than frozen water molecules at 0 degrees. This is also why it’s best to quickly close the freezer door; room-temperature air flooding in will absolutely raise the temperature. 
• Don’t leave anything in there too long. While the freezer is great for dramatically extending the life of food, if you wait long enough just about any frozen food will decline. It will eventually dry out, flavors may fade and fats will go rancid. Depending on how the food was handled, freezer burn could set in in days or it could take years. 
• Know which foods have the shortest frozen lifespans. As discussed above, proteins tend to be most susceptible to quality losses from freezer burn, while foods containing fats and oils may lose quality as rancidity occurs over time, potentially alongside freezer burn. Foods with specific frozen structures, like ice cream, could also suffer from texture issues if the temperature fluctuates too much.
• Understand that the food had a life before it reached you. While manufacturers and retailers generally take pains to maintain the cold chain, if a food is handled poorly during shipping or at the store, it may suffer from freezer burn. Not much you can do about that.

All that said, I freeze A LOT of food and sometimes don’t get to it as quickly as I’d like. Even so, it’s fairly unusual for me to encounter freezer-inflicted damage that renders food inedible.  I do often come across clumps of ice, but by the time the food is heated up, it’s as if that frost was never there. In fact, I wish I had more pictures for this post, but I really don’t find my food gets problematically freezer burnt all that often. 

It’s also worth keeping in mind that freezer burn can vary in severity. Recently, I put a loaf of bread in the freezer and didn’t stress about tying the bag up super tight. The toast I made a week later? It was passable, but it had a vague cardboardy taste that wasn’t ideal. Ever since, I’ve been storing my frozen bread in a heavier bag that I make sure to seal well.

My favorite approach to avoiding freezer burn (and food waste generally) is to view the freezer as short-term, rather than long-term storage. Yes, many foods theoretically could be good in there for a while, but I’d rather use them as I need them than hoard them for so long I forget about them and risk encountering something that doesn’t taste so great.