New Freezer: Keeping freezing cold the longest in the meantime?

[AnthonyL]

Swapping freezers tomorrow so contents will need to be put in cool bags/boxes (including Esky for those that have been to Australia).

What can I shove in the freezer tonight that will keep the contents coolest for longest whilst in temporary storage tomorrow? I'm looking at household stuff. I've already got those blue freezer blocks for picnics etc, and I've put a few plastic pint milk containers full of cold water, but would I be better adding salt to them?

Also:

How long should the new freezer stand before switching on?

How cold should the freezer be before stocking up? There seems some logic in filling it with cold stuff fairly early on rather than have it freezing air, is that logical?

[Jeremy Nicoll - news posts]

I might be inclined to put stuff into bin bags, and then those into another bin bag (and repeat?) or bubblewrap? to get layers of trapped air and also waterproofness, and then wrap those in spare duvets.

[Scion]

AnthonyL put finger to keyboard:

Get stuff packed as tightly as possible, with your freezer blocks/water containers on the outside edges if possible. Don't open the door after unplugging.

24 hours was the perceived wisdom a decade or so ago, for a freezer that had been on its side.

I'd get it to temperature first - there'll be an indicator to say if it is too warm - the walls will be cold then. Only then move the stuff from the old freezer. Most freezers have a Fast Freeze option; use it.

[mark]

Fill all voids with bags of water, to be used as temporary coolants. Turn old freezer it to max coldness. Salt wouldn't make it colder than plain water in the same freezer. Would thaw more quickly.

mark

[SteveW]

But if it is warming up and thaws at a lower temperature, wouldn't the latent heat of fusion mean that it absorbs heat in melting at that lower temperature and holds the contents of the freezer colder while it does so?

SteveW

[mark]

Yes, but theoretically insignificant I would suggest in this scenario, let's keep it sensible. Plain ice also experiences an endothermic change on melting.

mark

[AnthonyL]

Should have said, free removal of old unit with the delivery saving a fair bit of hassle.

[mark]

I see no reason why you can't put your frozen foods into the new freezer complete with icepacks etc. Just don't switch it on for the advised period (24hrs?). The new freezer will be well insulated.

mark

[Mr Pounder]

Your new freezer will be stored and transported standing up. It will be on its side only as it is carried into your house. Keep your old freezer plugged in, plug in the new one and put your food in it. This waiting 24 hours business is a load of bollocks.

[SteveW]

Yes, but at 0°C, whereas salt ice can be anything down to -21.6°C depending upon concentration. I honestly don't know how much difference this would actually make, but there is some.

SteveW

[Bill Wright]

A phenomenal amount of insulation was the answer for us when I helped a friend who has an hotel empty a 22 cubic foot freezer. We had some warning though. I had some blocks of steel about 10" x 10" x 2" so I put them in the freezer for three days beforehand. I put all the food and the steel into two tea chests. I put down a lot of rugs on the floor, one on top of the other. On these rugs I put a parcel of insulation material with the tea chest at the centre. I used many duvets and blankets, and a lot of bubblewrap and expanded poly packing material that was kicking around. The whole thing was about six/eight foot cube when we'd finished. This was in a sort of large storeroom, unheated, but ambient was +26 during the day. It was actually

36 hours before we opened the parcel and the food inside was at -17.5 (it had gone in at -20) so it was OK for him to use.

Bill

[Nick]

Lovely! Got any pics?

[Andrew Gabriel]

A big difference. Most food items freeze at a temperature some way below zero because of the salts in them. If you use plain ice, it will warm to it's melting point at 0, and stay there for a long time as it absorbs the latent heat to melt it, whilst the food has thawed. If you add enough salt to drop the freezing point to, say, -15C, then it will warm to -15C and then stay there a long time absorbing the latent heat, whilst keeping the food mostly frozen at -15C. This is how ice packs work (except they use a different antifreeze to drop the freezing point).

[SteveW]

This was basically what I was thinking of, but it was the time element that I was unsure I about - ie: how much of a pause in the temperature curve it would introduce at a useful temperature.

SteveW

[Steve Walker]

I have always powered-on new fridges and freezers immediately after unpacking. Never had a problem.