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How long does a freezer stay frozen when the power goes out?

woodgears.ca

11–20 of 384 posts

Re: How long does a freezer stay frozen when the power goes out?

#11
You want the contents to remain BELOW 0C, not hovering at 0C while everything melts.

You can do this by adding some salt-water bottles, which have a lower melting point, and will therefore absorb a lot of heat (heat of fusion) well below 0C. Eg add 250g salt/liter gives melting point of -18C.

Of course you waste some space on useless salt water vs potable - maybe there are better alternatives, eg fruit juice? Milk? Honey?

Re: How long does a freezer stay frozen when the power goes out?

#12
post #9

Related ... the last time I was in the market for a chest freezer (a "deep freeze") I wanted one that showed a log of temperature over time ... This, essentially, does not exist. It appears that there are laboratory freezers that support this (very simple) feature, but they are relatively small and very expensive . A better way to go is an electricity monitor on the plug, where you track electrical power over time an…

You could just freeze a cup of water, and then stick a penny in top of it. If you ever come back to find your penny embedded or at the bottom of the cup, you know your freezer thawed out at some point

Re: How long does a freezer stay frozen when the power goes out?

#13

If you can restock the freezer with ice, you can keep it cold for several days easily. Spoken from experience, thanks PG&E.

You’re not wrong, but at that point it’s basically just an ice chest—a bunch of ice will keep perishables cold, whether it’s in a fridge or a portable cooler or whatever. Not as efficient, maybe, but a modern fridge is already quite efficient at retaining coolness, so I don’t see why this isn’t a permanent solution!

I actually went through this last week. The problem is that, if the power goes out (presumably without advance warning), a bunch of triage to basically turn your freezer into a cooler for critical items is going to cost a bunch of the stored cold air.

I'd probably go instead, if you have a cooler, with buying a few bags of ice if you can and quickly pulling out high value/especially perishable items and putting them in the cooler.

Re: How long does a freezer stay frozen when the power goes out?

#16
post #9

Related ... the last time I was in the market for a chest freezer (a "deep freeze") I wanted one that showed a log of temperature over time ... This, essentially, does not exist. It appears that there are laboratory freezers that support this (very simple) feature, but they are relatively small and very expensive . A better way to go is an electricity monitor on the plug, where you track electrical power over time an…

> without resorting to weird solutions with raspis dangling temp wires into the freezer ...

Well, I had a solution up till that line. There's gotta be an elegant way to set something like that up on top of the fridge out of sight with clean cable management into the freezer.

Re: How long does a freezer stay frozen when the power goes out?

#18
A test with the freezer as full as possible with just water would be interesting as a best-case set of data points to compare against.

I always keep containers full of water in the bowels of my refrigerators/freezers only removing them when the space is required for food. There's not much sense in keeping empty volumes of air in a refrigerated space.

Re: How long does a freezer stay frozen when the power goes out?

#19

If you can restock the freezer with ice, you can keep it cold for several days easily. Spoken from experience, thanks PG&E.

Where do you get ice if you are out of power?

You can easily be out of power and the grocery store a couple miles down the road not be.

Re: How long does a freezer stay frozen when the power goes out?

#20
post #9

Related ... the last time I was in the market for a chest freezer (a "deep freeze") I wanted one that showed a log of temperature over time ... This, essentially, does not exist. It appears that there are laboratory freezers that support this (very simple) feature, but they are relatively small and very expensive . A better way to go is an electricity monitor on the plug, where you track electrical power over time an…

Such data might be interesting to look at, but as long as the freezer does its job (aka keep everything stored within it fully frozen), what's the point in having that data?
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