No power to freezer for 6 days but it didn't defrost. Does that mean it stayed below freezing?

Factual Questions
1

Two days short of a Hanukkah miracle.

After a 6-day power outage, the sides of our chest freezer still had the same frost build-up on the interior walls ( 1/8-1/4") as before the outage. Doesn’t that thick a layer only accrue over time? Does that mean the interior never got above freezing, so the meat is safe to eat?

It’s a basic 8CuFt chest freezer, the kind with a door that lifts open on the top. It’s in an unfinished basement, which hovered around 50 to 40F (or lower) during the outage. It was packed to the brim with frozen food.

The meat is all vacuum-sealed, so there’s no visible frost/ice inside the packages (i.e. I can’t tell if they thawed and refroze).

There is no layer of ice at the bottom of the freezer.

I didn’t open the freezer at all during the outage. I don’t know exactly when the power came on (we weren’t here), but when I did open to check, it would have been no more than 12 hours after the power came back. The level of frost on the sides was pretty much the same as it was before the power went out.

It’s a frost-free model, but still gets frost on the interior walls over time. When we’ve defrosted it in the past, the build-up melted and drained out the bottom and didn’t return for a long time after we plugged it back in. And when it did, it grew very slowly (months at least) on the walls from a thin layer to a thicker “we’ve got to defrost again” layer.

If the freezer did go above zero during the outtage, wouldn’t the frost on the side melt, collect on the bottom, and refreeze down there and then take a long time to rebuild the layer on the sides?

We dumped everything from the regular refrigerator/freezer in the kitchen, but from the above it really seems like the mass of the stored food, plus the freezer design/insulation, plus the low ambient temperature, plus the seemingly unmelted layer of frost and lack of ice on the bottom suggest that it never got above freezing in there — and hence the meat is still in the same state it was before the outage.

This assumption really hinges on the thought that if it did get above 0 in there, the existing frost would have melted and stayed put on the bottom, not gone into the air and condensed as a layer of frost on the walls in the handful of hours after the power returned. But that’s just an assumption ---- is the meat safe to eat?

2

I wouldn’t have any qualms about eating it, but I once killed and ate a wild chipmunk, so I’m probably not the best authority on what’s safe to eat vs not.

3

Your freezer probably holds things at about 0 degrees but food won’t even start to defrost until it gets close to 32 degrees. If the ice had melted, it would have formed a pool at the bottom of the freezer and refrozen. You note that there’s no pool of refrozen water. That suggests that the temperature in the freezer stayed below freezing for the whole time.

I’m a little surprised that it didn’t thaw in six days but it seems plausible given how cold the starting temperature was, how well insulated the freezer was, and the low ambient temperature around the freezer. Maybe you lucked out.

4

A tip for the future. You take a small see-through pill bottle and fill it half full of water. You then lay it on its side in the freezer until the water is frozen solid. You then stand the bottle up so the ice is standing sideways in the bottle.

From now on you can use the bottle as an easy way to see if your freezer has thawed out. If the ice is frozen in the bottom of the bottle, you know it melted and refroze. As long as you can see it on the side of the bottle you know the ice (and the other contents of the freezer) has remained frozen.

5

Assuming you’re talking about Fahrenheit, 0 is 32 degrees below the freezing point. Considering the basement was 50 degrees max, and the insulation of the freezer, I would have to guess it would take quite a bit of time for the interior to reach melting point. (Thaw point, whatever). Plus, if it was stocked with frozen food it would take much, much longer.

Same reason it’s been shown (no cite, can’t link to my professor from 20+ years ago) a fridge full of beer will cost less to run than an empty one. In a cool environment, with modern insulation and a start point of 0 degrees, fully stocked, the food is fine.

And if you’re really concerned, I’ll test it for ya. Starving and nothing in my freezer! :slight_smile:

6

Right, so for future reference, I’ll put a chipmunk and a small pee bottle in there (I have no idea why it took me three reads to see that it was “small see-through pill bottle”).

Thanks for backing up the intuition that the frost plus lack of frozen water at the bottom means it likely stayed below freezing in there. It really conflicted with the intuition that six days was way longer than necessary to thaw it out.

Also somehow thought that its temperature would have been just a few degrees below freezing, not way down at zero (all it has is a little 1-9 meaningless dial). I’m going to put a thermometer in there now to see what it’s ‘normal’ temperature is.

Kind of relieved. Insurance is covering most of the upstairs loss, but it maxes out at $400. There’s that upstairs alone, the chest freezer had a lot more in it. Glad to hear it’s likely safe to eat. Just to be sure, I’ll have a friend post here if we all die in a case of explosive botulism.

ETA@ Duffer. I’m pretty sure Cecil covered something like that a long time ago, but can’t find it. Or maybe it’s an ancient GQ thread. Sound familiar to anyone?

7

Missed the edit window after finding:

Does a refrigerator cool more efficiently when full?

Straight Dope column June 2006!

8

Assuming that you checked as soon as the power came back on, and there was still ice in it, then you know it never thawed even without looking for pooling. With the power off, there’s no way for the temperature to decrease, so if it ever thawed, it’d stay thawed.

That said, even if the ice never thawed, not even partially, it’s still possible that some of the food did. Pure water freezes at 32 F, but for impure water (i.e., the water in any food), the freezing point will be somewhat lower. 0 F is cold enough that pretty much anything you might plausibly have in there will stay frozen, which is why freezers usually run at that temperature.

Now, even if some of the food did thaw (but stayed below 32 F), it probably won’t go bad, per se. Even those bacteria which aren’t completely dormant at that temperature will only be reproducing extremely slowly. But repeated freeze-thaw cycles can cause freezer burn, and worsen the taste of the food.

So the lesson is, as always, give it a taste, and if it tastes bad, then throw it out.

9

Hadn’t seen that article, but yeah, pretty much the same thing I was taught (told, whatever).

When’s dinner damnit?!?

10

But was the meat itself still frozen? Freezer walls are one thing, the contents are another.

11

I suppose it’s a fair question, since it focuses on the point of having a freezer – keeping foodstuffs frozen.

But practically, where is the meat going to get heat energy except through the walls or door of the freezer? Unless the meat contains its own heat source, the walls would defrost before (or at least simultaneously) with the food thawing.

12

Our power was out for exactly 7 days during the Montreal ice storm of '98. We got back about a half day after power was restored and our freezer was in pretty much the same state as described in the OP. The temperature in the house when we got back was 34, but there had been some heating in the meantime. We were advised to throw out the contents of the freezer. We didn’t. What we did do was make a giant stew from all the meat and left the rest–mostly baked goods. Everything was fine. I doubt the freezer (a chest) got anywhere near 32.

13

The meat won’t be any warmer than the surroundings, but because it’s not pure water, its melting point will be lower. So it might be thawed even though it’s still cold. Which, again, isn’t dangerous, but might decrease the quality.

14

After a blackout in the 70s I found to my surprise $500 that had been frozen out of sight. I can’t even say now why I forgot I put it there, because I forgot then the first time.

FWIW

15

I can see you’re a good candidate for this thread.