What exactly is freezer burn and can we prevent it?
There seems to be a lot of confusion about what exactly freezer burn is. According to Wikipedia, freezer burn is a condition that occurs when frozen food has been damaged by dehydration and oxidation due to air reaching the food. Well, unfortunately that is not accurate. And here’s why. When they say air by implication they are talking about moisture. The assumption being that when you see ice crystals on the food its from moisture getting into the food. The problem with that is, refrigeration systems are designed to remove moisture. Your freezer is actually a very dry place.
Most people use freezer bags made of plastic to store food in their freezer. In fact, if you take something out of the freezer and try to thaw it out, you’ll put it in hot water to try and accelerate the thawing process. But does the bag fill up with water? Does air or moisture migrate into the bag? The fact is air can’t pass through a typical plastic bag. Otherwise we wouldn’t need warning labels on plastic bags that say keep away from children, this is not a toy.
Frozen food manufacturers go to great lengths to displace any air or moisture inside the plastic bag where they put the food. In fact, in the packaging process at the very end of the line, just before the bag is sealed, a shot of dry food grade nitrogen is shot into the bag to displace any air and the bag is sealed. And even that does not prevent freezer burn. Take a look at the picture of some frozen food that was in my freezer for an extended length of time. The bag was never opened and even though the bag is still full of dry nitrogen, you can see extensive freezer burn has taken place.