Comment: Icebox Coolers & Eskys

No mention of salting the ice to make it last longer in the ice box article. I would really like to know if there is any truth in that practice. I have been told by some people that throwing a couple of handfuls of salt on the ice helps to preserve it. I have also heard that using salt water to make ice makes it last longer. Maybe it is just an urban myth too.
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Reply By: Herbal - Sunday, Oct 06, 2013 at 14:23

Sunday, Oct 06, 2013 at 14:23
Hi Coldee,

No myth...It's true !

Well partly true. I would have to check through my text books to see it salt makes ice last longer. But it certainly does make it colder !!

Manual ice cream making machines still use salt.

Using salt water to make ice I think would be a myth...But again, I have forgotten more about this sort of stuff than I care to remember...Saturated salt water does not freeze - the water freezes but the salt gets "pushed" out.

But, yes putting salt on your ice will make it colder.
AnswerID: 519267

Reply By: Herbal - Sunday, Oct 06, 2013 at 14:35

Sunday, Oct 06, 2013 at 14:35
I was going to run off to my text books...Silly me...I have got the intergoogleweb thingy :)

No, it will not make the ice last longer...Because it makes it colder !! What was that ??

Salt lowers the freezing point of water. Which means the water will remain a liquid at much lower temps. But it also means that the ice will get colder as the salt reduces the temp.

This means that although it gets colder the freezing point it lower and so the ice will actually melt even though it might be as low as minus 20c.

See ?? Easy :)
AnswerID: 519269

Reply By: gbc - Sunday, Oct 06, 2013 at 16:05

Sunday, Oct 06, 2013 at 16:05
Throwing in the salt simply allows the existing water in the slurry to go below zero degrees and keep the whole mess colder for longer (brine).
The upshot of this is that any sealed receptacle containing fluid (AMBER FLUID) will freeze inside the water slurry and blow the caps off all your bloody stubbies, smash a few and create an even bigger mess.
But hey, if beer slushies are your go, its a brilliant idea.
Excellent for fish, not excellent for grog/veges and anything else you don't normally freeze.
It takes a few decent handfulls of pool salt in a 60 litre esky to create a decent beer smashing brine though.
AnswerID: 519278

Follow Up By: Herbal - Sunday, Oct 06, 2013 at 16:35

Sunday, Oct 06, 2013 at 16:35
That's all very good and well...but what decent beer drinker is going to have a 60 litre esky?? What if a few mates come round ?? What then ??

What you need is 10 of those 25kg bags of pool salt from Bunnings...hang on...a mate has just turned up with his refrigerated B-Double...I gotta go :)
FollowupID: 799315

Follow Up By: Member - Coldee - Monday, Oct 07, 2013 at 14:03

Monday, Oct 07, 2013 at 14:03
Actually heard it from a trawlerman but never used it myself. That's why I asked. Not sure about the beer slurry though.

From what I understand a bit of salt goes on a solid block of ice at the bottom of the esky, then normal ice pieces on top. The bottom block keeps the rest of the ice from melting. Frozen prawns are not ideal either.

Thanks Herbal. I had an inkling that is what I was told but, as I said, it is something I have never tried so I wasn't prepared to comment too much.
FollowupID: 799371

Reply By: Member - liftnlock lux - Tuesday, Oct 08, 2013 at 09:04

Tuesday, Oct 08, 2013 at 09:04
Try making large ice blocks from a plastic rectangular container. Place it in the freezer and when its 75% frozen youll notice a portion in the middle of the block still fluid, poke a hole in the top of the block and pour it out and replace the water and refreeze. You can do this many times and what happens is the cloudy part of the ice block is reduced as its the clear ice that lasts longest and stays coolest.
i've done this for years and i can get 6 days on the beach without a problem. If you vacuum seal your meats they can stay in the water at the bottom of the eski without perishing.
Hope it helps
AnswerID: 519359

Follow Up By: Member - liftnlock lux - Tuesday, Oct 08, 2013 at 09:32

Tuesday, Oct 08, 2013 at 09:32
If you dont feel like messing around try putting a 10 litre eski (lid and handle removed) into the freezer with 100mm of water in the bottom and it will produce clear ice without the fuss but be prepared to wait for a while.
FollowupID: 799438

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