How long does a freezer keep food good?

Factual Questions
1

I had a repair guy out to service my (built-in to refrigerator) freezer on Saturday. During the visit, he told me that if I expect the freezer to keep any food good longer than 2 or 3 weeks or a month, I’ve got too high expectations.

He says freezers are designed to keep food good for 2-4 weeks and no longer. I told him that my past refrigerator freezers would keep food good for much longer, 2 months, 3 months, sometimes for a year or more of it’s properly packaged or unopened. He thought I was lying or misremembering.

My complaint about our freezer is that, since we bought it, frozen food becomes frostbitten after 2 weeks. Even if it’s still in the original wrapper from the store.

Then he starts telling me that I can’t expect food to stay frozen from the store to the apartment. I pointed at the keeper bag on top of the fridge, which is designed to insulate food and keep it cold. He tells me it won’t help and my food is no longer frozen when I get it home.

I tell him that since I got this fridge, I have had to develop a strict protocol for getting my frozen food home quickly and still cold in order to attempt to maintain food quality. I get it from the frozen section at the store, rush it out to the car, run the a/c the whole way home while the frozen food is inside an insulated bag, when I get home it’s rushed directly into the freezer.

I point out that with past freezers, I haven’t had such a protocol - I would just bring the food home at my own pace, toss it in the freezer, and 6 months later, it would still be good. Again, he assumes I’m lying or crazy.

I point out that the thermometer that we keep in the freezer sometimes says the temperature is too high. Without even looking at it, he says that those thermometers (the kinds that a consumer like me would buy) are no good, and are often off by as much as 7 degrees. Plus, he says, when you open the door to look, the temperature changes within 10 seconds, so you can’t trust a reading you get off it.

I told him that we look at the thermometer within 1 second of opening the door. If it’s off by 7 degrees, then when it says it’s 25 degrees that means it could be as high as 32, or as low as 18 degrees. That’s not a good range for food in the freezer, either way. He also tells me that in the front is not the place to keep such a thermometer, it should be in the back of the freezer.

He said that we should make an effort to eat our frozen food within 2 weeks if it’s frostbitten within 2 weeks. He also says not to put things in the freezer that have been opened and expect them to last.

I point out that I sometimes get fudge bars, individually wrapped in a box. Say, 36 of them. If I eat 1 a day, that’s going to last me over a month - I can’t eat them within 2 weeks. But since they’re individually wrapped, we would assume there’s not too much moisture transfer between the fudge bar and the refrigerator around it. So how come in the first 2 weeks, they taste ok, but after that time they taste like frozen sand and there’s visible frosting inside the package? Apparently my expectations are too high - the repair man told me he would never put a popsicle in the freezer and expect it to last an entire month.

So, I want to know - how long should I expect food to last when I put it in the freezer? We’re talking unopened food from the store, often with an expiration date far in the future. For example, I bought some frozen french toast at Trader Joe’s and it says it expires 9/12/2009. Should I listen to the repair man and force myself to eat it within a month? What if it goes bad in 3 weeks (badly frostbitten) - is that to be expected, or is there something wrong with the freezer?

2

The freezer burn appearing in your new freezer but not your old one probably has something to do with automatic defrosting. Older freezers would have to be defrosted manually, but newer ones tend to do it by themselves. This can cause freezer burn, because of the fact that the temperature in an automatically defrosting freezer tends to fluctuate a lot.

The only way to completely fix this problem, to my knowledge, would be to poke around in the freezer and take out/disable whatever part initiates the defrosting, but I’ve no idea how to do that, or even if it’s generally possible. You can try to keep your freezer’s temperature more stable by putting a lot of stuff in it—a couple gallon jugs of water would work, if you have the space.

It should be noted, though, that food with freezer burn isn’t any more dangerous than food without. It merely isn’t that appetizing. So when your food goes “bad” is a matter of subjective taste.

3

True, but when a fudge bar (which is supposed to be a tasty treat) has the texture of frozen sand mixed with soft rubber, and the taste is horrid … you will want to throw out the rest of the box.

And does your freezer cause individually wrapped fudge bars to be freezer burned beyond your desire to eat them in two weeks?

4

Seconded. A defrost cycle is actually a heating cycle, and is horrible for keeping food fresh as long as possible. But unless you can afford to replace yours with a manual defrost freezer, you’re basically stuck.

Freezers should always be full for greatest efficiency and to keep them from defrosting if the power goes out. Any empty space should be filled with jugs of ice.

Also, never add more than 10-15% of the freezer’s capacity of unfrozen food at any time, and always pre-chill food in the refrigerator before freezing. Adding warm food or even too much pre-chilled food will partially thaw the food already in the freezer.

Pre-packaged food and grocery store wrapped meats are generally not packaged very well for long term storage. They will freezer burn or otherwise deteriorate pretty quickly. Here is a table that shows how long you can expect decent quality from frozen food and more tips. You can effectively double the storage times listed with a vacuum sealer (but don’t buy the cheap generic rolls of bag material, as they’re garbage).

Me? I use my huge manual defrost freezer for long-term storage, and the little auto defrost one attached to the fridge for stuff that will be eaten up relatively soon. I’d fully expect my fudge bars to be nasty and gritty in a few weeks in the frost free freezer, but fine for a few months in the manual defrost freezer.

5

That’s far too warm. A freezer and its contents should be at 0 degrees. At worst, maybe as high as 8 degrees, but at that point, you’ll have trouble keeping ice cream frozen.

For a fridge, the temp should be between 35 and 38. The US FDA sets the maximum temp for food in a fridge to be no more than 41. Strangely, they’re silent on an actual freezer temperature, and only say that food is to be frozen solid.

ETA: Just noticed the “built-in” reference. Tell your repair guy that there’s a reason the brand name is Sub-Zero. And look for a new repair guy.

6

This is the repair guy sent by Sears on the fridge we bought at Sears with a 5 year extended warranty.

In the 5 years we’ve owned it, the fridge has always frostbitten food in 2 weeks. We’ve called and they’ve sent repairmen several times, but it’s never been “fixed” to the point where food in the freezer doesn’t go bad in 2 weeks.

Previous refrigerators I’ve owned (including ones that auto defrost) keep food for far, far longer. 2 weeks seems like refrigerator time, not freezer time. I mean, if there’s food that would keep in a refrigerator for 3 weeks, why would it only last 2 weeks in the freezer?

7

Having maintained freezers of the walk in variety, the general rule is -10 degrees F
for the longer term storage. 0 degrees F for a line freezer to keep the open bag of french fries or chicken strips in just before cooking. Might well be just the regulations in this area, but IIRC it is a State regulation for restaurants.

32 degrees F is the freezing point of clean water, any solids in the mix will cause the freezing point to lower.

8

We’ve given you the likely problems. Were you in my lab, I’d give you a data logger to put in the freezer overnight, and a quick look at the data tomorrow would tell you exactly what is wrong. Since you probably don’t want to fork over big bucks for a data logger you’ll never use again, here’s the expedient version:

  1. Calibrate your thermometer against a few others to make sure it is operating correctly at whatever temperature your freezer is running.
  2. Check the temperature of your freezer many times over a period of a few days. To eliminate error caused by heat entering when you open the door, put a glass of oil in the freezer, and put your thermometer in that.
  3. Graph time on the x-axis, and temperature on the y-axis (if the data does not show an obvious problem without doing so.)

I’ve run data loggers in many freezers, and what you should see for a frost free model is a running temperature of about -20C (-4F) and usually 2 cycles per day where it briefly heats up to 0C (32F). Pretty much guaranteed your freezer either has the low setting too warm, or the defrost cycle is staying on too long or coming on too often.

9

Good info, masterofnone.

When the repair guy was here, he did swap out the “defroster board,” and said the defrost mode should last 18 minutes. He told me to set a timer for 20 minutes, he’ll trigger the defroster, and we’ll see when it turns off. Then he tweaked something that he said should lower the defrost timer so even if 18 minutes was too long, this will be better.

When he said the defroster turned off, the timer was at 8 minutes remaining, so the defrost cycle lasted 12 minutes.

Should either 12 or 18 minutes cause frost crystals to form (these eventually turn into solid ice over a few weeks) like I’m describing? How long would too long in defrost be?

Also, I told the guy while he was here that a previous repair guy told us to stuff the freezer full of food rather than leaving it empty, and he told us that won’t matter at all. FWIW, it’s just my girlfriend and me here, and we don’t open and close the freezer a lot.

Oh one other thing - the guy told us that if our freezer is acting like we described, that our refrigerator portion would be having issues also. We told him the refrigerator part has worked fine. (There was a period a few years ago where things in the far back were freezing, but it got over that, and the frostbite problem never stopped)

10

I agree and being the kind of person who always has thermometers all over the placeI can say all my freezers have always maintained -5F (-20C) with no problem and the food will keep for months. I would consider a freezer that is not keeping 0F to be faulty. The explanations given by the technician in the OP seem like BS to me.

11

But several people have said that a fridge will get up to a higher temperature during the defrost cycle.

The question is whether that is enough to cause frostbitten food within 2 weeks. If not, something else is wrong with the fridge (like, a longer than normal defrost cycle, or something else).

12

You’re probably going to have to do what masterofnone suggested and collect data. If you find a cheap thermometer narrow enough to fit inside a soda bottle, I’d recommend using vodka in a sealed bottle rather than oil. Put at least two thermometers in, one in the liquid for long term trend readings, one bare for live temperature readings. If you want to be really fancy you can do a whole set with different quantities of thermal buffer fluid.

Alternatively or in addition, stick your fudge bars all throughout the freezer. Note if some spots seem to have bigger problems with freezer burn than others. Those spots are where you want to put the thermometers if you do data runs.

13

Varying the temperature just a few degrees will cause the formation and growth of ice crystals over time. If you freezer is varying from 0 to 18 degrees it would not take long for the food to be damaged.

Your home freezer should vary no more that += 1 degree with the door closed. When you open the door all the cold air will begin to fall out.

A Sub Zero unit has two seperate refigeration curcuits.

Most other built in units have just one curcuits. With the stat in the refrig side and a manual control that deverts air to the freezer side. (some brands are oposite). This can cause one side or the other to varry a little in the temp setting.

NOw to the repairman you may be stuck. But if you really want your unit to work call a pro. I do not know how many jokes I have heard about store or warrenty service people.

14

Another thought

On the deforst function.
When your unit goes into defrost (usually once or twice daily) the compressor and the evaporator fan turns off. A cal-rod (like the element in an electric oven) is energised. The cal rod melts any ice off the evaporator coil. If all the ice melts a thermastat will shut off the cal-rod.

If everything is working properly the freezers temp should not raise over 1 degree.

15

Your repairman is an idiot. I’ve kept food frozen in freezers for 6 months to more than a year with no ill effects. So long as the food is properly sealed to prevent loss of moisture (which causes freezer burn), and so long as the freezer maintains the internal temperature at a temperature of 0 deg F or lower, food should last in a freezer indefinitely.

16

I agree that the serviceman referred to above sounds like a class-A idiot with his 7-degrees and 10-second comments. But in reading this thread, I wonder what the temp is in your freezer. The above suggests (but does not state) that it’s about 25’. Several knowledgeable replies have indicated it should be below zero, and that if it’s not there’s your problem.

I’ve been expecting you to respond with a declaration of the temp, but instead you seem focused on the defrost function. If I understand correctly, worrying about the defrost when the basic temp is 30’ too warm is like rearranging deck chairs on the Titanic.

So please quench my burning curiosity and tell us, what is the temp reading in your freezer.

17

It is **mostly **-10 to 0 degrees, however, we have opened the freezer door and seen the temperature at 10 or 20 degrees fahrenheit. The repairman tells us that it gets that temperature during the defrost cycle, which is why I’ve been focusing on the defrost cycle.

If it gets to be 20 degrees for the 18 minutes the repairman states is normal for the defrost cycle in the freezer (which seems perfectly reasonable to him), then my question is, “is that long enough to form ice crystals.”

However, Snnipe 70E says that the temperature should not raise 1 degree during the defrost cycle, assuming even if it is 18 minutes. This is because the door to the freezer is not open during the defrost cycle, and that cold, cold air is still in there, right?

So, the temperature in the freezer should never get above 0 degrees, and could very well be below 0 degrees.

How much should it fluctuate? I sometimes see it at -10, sometimes at -4, sometimes at 0. Is that a tolerable fluctuation? If it’s at 10 degrees one morning, 20 degrees a few mornings later, it shouldn’t be because of defrost, there’s probably something wrong with it, right?

18

Just to be clear, we are not opening and closing the door every 10 minutes to check. Since his visit on Saturday, we either make a point of looking when we happen to be opening it anyhow … or open it first thing in the morning, or only after it hasn’t been opened for a few hours.

I’m thinking about getting a thermometer that monitors the temp and lets us see it without opening the door. Does anyone know if this keeps a log or history?

It would be nice to know if at 3:24am it went to 20 degrees for 30 minutes, then back down to -10. That would sure explain a lot…

19

So I answered the question about the temp of the freezer. It’s mostly -10 to 0 degrees, but sometimes we open the freezer door and it says 10 or 15 or 20 degrees. The service guy tells me that’s the normal temperature that a freezer reaches during defrost, but it seems to me that you guys are telling me that it’s not.

Well, I’ve requested that Sears send another repairman (free of charge) and we’ll try this one more time, but I’d like to have as much information as possible before his visit so that I can talk to him coherently about it.

Does anyone know if this thermometer has a history function? I didn’t see it listed in the functions, but a reviewer said it does - I want to make sure he’s talking about the right model before I buy.

20

If it’s the one in the picture, it does have a memory function - it displays max/min.

Every auto-defrost freezer I’ve ever put a data logger in goes well above zero briefly twice a day. I don’t know what **Snnipe 70E **is talking about, but it may be specific to Sub Zero brand.

Note that this temperature spike will not show up if you suberge your thermometer in oil or alcohol, as that is to simulate what is actually happening to the food, instead of the air in your freezer. If you get a thermometer like the one in your link, it will display the air temperature. Unfortunately, this will only display the maximum temperature, and not the time at that temperature, so it won’t tell you if the defrost is staying on too long unless you time it just right.