Freezer Burn
Most recent answer: 10/22/2007
Q:
What is a bad freeze burn?
- Qi Han
- Qi Han
A:
There are two things that come to mind when someone mentions "burns" in the context of cold.
One is mentioned on this site -- liquid nitrogen is very cold and will freeze things it touches. You have to be very very careful when handling things as cold as liquid nitrogen (the rule is -- don’t touch it at all). Even dry ice (solidified carbon dioxide) is dangerous and should be handled with gloves. If you are out on a cold, windy day, it is easy to get frostbite. All of these kinds of things occur because the water in your skin and just under it can get so cold it will freeze. Water likes to make sharp-edged crystals, and these crystals can grow and poke through cell membranes, causing irreparable damage. This is what frostbite is.
This process happens so fast and hurts so much when touching stuff like liquid nitrogen and dry ice it is sometimes called a burn. It really isn’t a burn at all, but rather is the effect of solidification of liquids doing damage to tissue.
Another kind of freezer burn (hopefully, much more common) happens in the freezer to, especially, meats which are left in there without some kind of airtight covering, for several months. Water evaporates at all temperatures, and even will escape its solid state. Ice will slowly shrink even without melting first, as water molecules escape from the ice surface and fly into the air. This process is called "sublimation". Many freezers today have cold, dry air circulating inside them, which speeds up the process.
The meat (or other food item) left uncovered in the freezer will then dry out and shrivel up. Meats turn brown when this happens. It really looks as if the stuff has been burning, even though it has been in the freezer.
Tom
One is mentioned on this site -- liquid nitrogen is very cold and will freeze things it touches. You have to be very very careful when handling things as cold as liquid nitrogen (the rule is -- don’t touch it at all). Even dry ice (solidified carbon dioxide) is dangerous and should be handled with gloves. If you are out on a cold, windy day, it is easy to get frostbite. All of these kinds of things occur because the water in your skin and just under it can get so cold it will freeze. Water likes to make sharp-edged crystals, and these crystals can grow and poke through cell membranes, causing irreparable damage. This is what frostbite is.
This process happens so fast and hurts so much when touching stuff like liquid nitrogen and dry ice it is sometimes called a burn. It really isn’t a burn at all, but rather is the effect of solidification of liquids doing damage to tissue.
Another kind of freezer burn (hopefully, much more common) happens in the freezer to, especially, meats which are left in there without some kind of airtight covering, for several months. Water evaporates at all temperatures, and even will escape its solid state. Ice will slowly shrink even without melting first, as water molecules escape from the ice surface and fly into the air. This process is called "sublimation". Many freezers today have cold, dry air circulating inside them, which speeds up the process.
The meat (or other food item) left uncovered in the freezer will then dry out and shrivel up. Meats turn brown when this happens. It really looks as if the stuff has been burning, even though it has been in the freezer.
Tom
(published on 10/22/2007)
Follow-Up #1: freezing skin tags
Q:
My doctor used liquid nitrogen to freeze skin tags from my arms. Now I have these red spots all over them. Will the burns clear up? My arms look like I have a disease.
- charles (age 76)
mesa,az. USA
- charles (age 76)
mesa,az. USA
A:
We aren't medical doctors, but I can say that whenever I've had tags or spots frozen off the skin healed after a while.
Mike W.
(published on 01/02/2014)