Why doesn't food in a freezer last forever?

September 5, 2009 12:50 AM

Why doesn't food in a freezer last forever?

Frozen food i buy from a super market and even the user guide that came with my freezer both say that food can be stored from 3-12 months.

What would it take for food to be permanently cold stored?
i am thinking that storage containers that are totally air and moisture proof would be needed and likely a freezer that is a lot colder then a general household one would be required?

The reason i ask is that some of the home cooked meals in my freezer are nearing the point of no return. they are getting freezer burn despite being in what i thought where well sealed tupperware.
i would like to maximize the time i can get from the food in my freezer to enable a greater variety of ready to heat meals

posted by Phcyso to home & garden (4 comments total)

Freezing doesn't stop chemical reactions like oxidation (unless you're freezing to absolute zero, I guess). It just slows them down. Also, evaporation happens a whole lot faster at sub-zero temperatures--sublimation, actually.

This wikipedia article on freezer burn will answer your question.
posted by halogen at 1:01 AM on September 5

Buy a chest freezer.

Most refridgerators have frost-free freezers, which have a heating cycle that melts any built up ice. This will dehydrate foods because of the freeze/thaw cycle.

Most chest freezers require manual defrosting, which means your food lasts longer.

Food can be permanently stored safely, it's just the quality that will deteriorate. Read this: USDA Food Safety
posted by wongcorgi at 1:02 AM on September 5

What your asking is about reaction rates. Some reactions are very temperature dependent and won't happen at refrigerator temperatures. To go to the other end of the spectrum, nuclear decay will merrily plug along at absolute zero.

For what you're looking for, you want your food to be well below freezing all the time and you want to minimize it's exposure to air and light.

So fear the defrost cycle, as has been said previously. Also, try to minimize the head space in your sealed container, or if you want to go really crazy, use a CO2 tank for home brewing or argon tank for a mig welder to fill the head space in your container with an inert gas. Light is probably not much of a concern in a freezer.
posted by Kid Charlemagne at 11:35 AM on September 5

The problem is not with the seal of the tupperware but with the air trapped inside it, for reasons explained by the Wikipedia article that halogen links to. A home vacuum sealer will extend (though not infinitely) the amount of time you can freeze foods without them being damaged by freezer burn. Just read and follow the instructions carefully; liquid-y foods have to be handled differently from solids, and fresh veggies generally have to be parboiled before freezing.
posted by Orinda at 12:30 PM on September 5