Freezer burn: It’s one of the worst food oxymorons – up there with non-alcoholic beer. How exactly does something burn in the cold? What kind of sorcery is this?
The YouTube channel SciShow recently answered this question the best way they know how – with science. Turns out, “freezer burn” is actually caused by dehydration. Over time, the water molecules in frozen food will sublimate, meaning they turn into vapor and float off, leaving your grub less delicious than it was before. This process happens more quickly when foods aren’t properly wrapped, exposing them to more oxygen, which is why vacuum-sealed frozen fish will last longer than, say, a plate of leftover sushi.
The good news is that food with freezer burn is still edible. Or actually maybe that’s the bad news since you don’t have as good a reason to throw it away. But either way, keep in mind that if you leave food in the freezer long enough, freezer burn is inevitable – so no, unlike fine wine, those microwavable dinners are not going to taste any better two years from now.