A Serious Question.... about ice, yep...ice.

[Jeepers Creepers]

We'll have the milk etc, in the gas fridge, but to keep our sports drinks (BEER) cold, i was going to take our rather old esky.
It still works OK and all that crap, but to keep the beer extra nice and cold, i was going to "salt the ice"

Now, I've never done the salt on ice before, but have been told, it will last longer and be colder.... is that correct?

The reason i ask, oh great camping guru's of the cosmos, is that I'm of the belief, that they salt roads to melt the ice in cold climates.

So, will salting the ice, make it colder and last longer (sounds like an ad for Mr. Wobbly nasal spray erection stuff) or will it melt the ice quicker?

I guess I'd really like to hear from someone that's done it before or has a science degree.

Oh alright, anyone can answer...... 

[fuji]

When I was a youngun and lived overseas in Sth Korea, the US Military used to throw salt on the icy and snowed in roads. It worked so I think that salt does melt the ice. I suppose you could buy some cheap pool salt and give it a try. Probably cost $15 total IMO. Cheers
Wayne

[HEM19X]

In the good old days, the local fish co-op used to freeze salt water for the trawlers to keeps prawns cool as salt water freezes at a lower temp than fresh.

We have a 2nd fridge in which we turn the freezer section down as cold as it goes, leaving the ice in that makes it last longer - However never tried salting ice as it makes the bundy & coke taste funny!

[Jeepers Creepers]

This is interesting, been googling the question.

Most seem to say, it wont make the ice last longer, but would make it colder.

You would think, if it has lowered the freezing temp of the water, it would have to last longer. 

I'm going to mix some salty water up later and freeze it and see how it goes.
The only real test i guess, would be to do two matching eskies in every aspect and do a mythbusters thing on it.

Still keen to hear from someone that has tried it.

[speewa158]

Buy a bigger Engel & dont do drugs 

[swoffer]

Yep , definately works . I'm a comm fisherman of about 30 years and in our pre refig on the boat days thats exactly what we used to do to get more life out of our block ice . Fish will actually freeze in a extra salty slurry .
As already mentioned tho the main drawback is it makes ya Scotch taste like pee 

[rodw]

It will certainly get your beer colder but expect to end up with frozen beer.  I remember doing this years ago using garbage bins as the ice chests, salt and ice to keep the beer cold on the beach near Tin Can Bay. The salt makes you thirsty, the beer freezes, you drink as much beer as you can defrost to quench the thirst and you wake up with the biggest hangover you can imagine!

In the old temperature scale, water froze at 32 degrees F and salty water froze at 0 degrees (-17.8 Degrees C). The temperature in a home freezer is -15 degrees C so you can see that you will have no trouble freezing your beer with salted ice.

Good luck!

[Jeepers Creepers]

OK,  i've mixed up the salty stuff in 3 separate 2 litre containers to place in the esky.

I'll turf a bag or two of party ice around as well and see how it works.

[UR-50-LO]

When I had my boat I'd make a slurry to keep any fish in good condition.
Started off with frozen salt water and would pour a bit of ocen water over the 2 litre ice blocks when we got to the boat ramp. Temp would get low enough to make your hands ache when you put them in the cooler and would semi freeze anything inside....

[SteveandViv]

The salt changes the chemical composition of the water which allows the water tb colder with out freezing. The bets test is to put two different ice cream container in the freezer and then check out how the standard water one freezes at 0 and the salt water one freezes at -4.

If you make the ice with salt before you go away then it will last longer in the Esky because it melting point is lower so the slurry is colder, make for a great beer in a -4 slurry than a 0 slurry.. Just adding salt to the ice will allow the water/ salt mixture to be liquid at a lower temp and it should  last longer, at the start in any case

this same principle was used on roads. By adding the salt the ice would melt to a slurry quicker and then run off the road. Wasn't so good for the rust factor though

[Tassie devils]

Triple j 11am Thursdays phone in doctor Carl he will know the answer

[JU5T1N]

I'm going to mix some salty water up later and freeze it and see how it goes.
The only real test i guess, would be to do two matching eskies in every aspect and do a mythbusters thing on it.

forget doing a Mythbusters, do the Brainiac version & get a Malene Espensen in her tight little nurse outfit for the photo's 

[Jeepers Creepers]

Its interesting so far, all 3 two litre plastic bottles have been in the freezer now for about 36 hours.

All 3 are "nearly" frozen solid, which is what i was hoping for. By Friday morning when we leave and remove them from the freezer, i'm thinking/hoping, i'll have 3 solid bricks.

Be interesting to see how they last too, as they are in the beer and coke esky only and i'm planning on throwing a wet towel over the esky lid during the day.

[edz]

Just dont do like a bloke at work did, He froze down three tubs of salted brine and put the block ice into his custom esky.with party ice over the top .
All was great......... at first....... till the ice melted down and the cans where bobbing in the melt water / ice slush.. then all he could taste was salt every time they tried to drink from the cans, he reckoned even wiping the can first didnt help .

[jclures]

We used to make ice for sale, if it was for a fishing trip or alike, we always added salt to the water before freezing, I always seemed to last longer with the salt, but it took longer to freeze down before using.

[Mallory Black]

I had a go earlier this year but my freezer didn't have the grunt to freeze salty water.
It was awesome to see whenever I took the container out and watched the condensation on the outside freezing, so that proved it was damn cold but in the esky I had no way of telling how cold it was after a day or so.
So went back to just using clean soft drink bottles with frozen tap water in them, if there was ice in it it was cold enough to chill stuff, when there was no more ice it became drinking water.

[Trex_s4m1]

how long do you need to go away for?
i have been using techniice ice boxes and dry ice sheets (reusable) for a few years now and they are great. pack smart and they last ages.
also they lower your freezer temp by a few degrees so you save on the freezer running costs
i have an 80L and 100L 80 is prob enough but the 100 is good for parties to fill her up with drinks.
hth
sam

[Burnsy]

Correct that salt water needs to be colder to freeze (by around 4 degrees as Steve suggests) however it really should make no difference.  If you have two 5kg blocks of ice both at say minus 10 degrees, whether they have salt in them or not should make no difference as they have the same thermal energy, ie 5kg at minus 10 degrees.

[SteveandViv]

Correct that salt water needs to be colder to freeze (by around 4 degrees as Steve suggests) however it really should make no difference.  If you have two 5kg blocks of ice both at say minus 10 degrees, whether they have salt in them or not should make no difference as they have the same thermal energy, ie 5kg at minus 10 degrees.

Yes and I for got to add which has been already that the salt verse water concentration is very high. Not like a few cups of salt per whatever of water but at a level that is considered a brine. This is also used in fishing as the brine solution is not soaked up as much as a pure water solution meaning when the fish is frozen does not turn into mush when re-thawed from cell damage. (wonderful thing doing a 4 year apprenticeship as a Chef, they teach you all kinds of Paku )

[Burnsy]

The chef and the scientist, what a fine team we make

So to sum up for the OP

Saline water has a lower freezing point but no additional ability to store thermal energy, as such, 2kg of non saline ice and 2kg of saline ice both at the same starting temperature (ie frozen in the same freezer for the same amount of time) should take the same amount of warm beer and time to bring the entire mix up to say 5 degrees.

There may be some minor variances such as if you take beer out along the way, for example as the ice slurry will be colder it may cause the beer to part freeze so when you remove a beer you will be removing a greater amount of thermal energy than if you remove a beer from the non saline esky.  Removing a greater amount of cold thermal energy each time in this manner will actually make the saline esky come up to the higher temperature quicker than the non saline. 

[ozbogwam]

Just use dry ice much easier and cleaner. We used to use it prior to the Waeco.

Would get a shovel full from BOC and make an inch or so layer on the bottom of the esky. Then a layer of newspaper and a tea towel on top then all the pre chilled food.

Then we'd grab a six can esky and fill it with dry ice. We would use this to chill our drinks in cans. They would be stored out of the esky then just grab one place on top of the dry ice and just rotate it around on the ice for a minute or two and nice cold drink.

[Patr80l]

or you could add sawdust.

http://en.wikipedia.org/wiki/Pykrete

[SteveandViv]

The chef and the scientist, what a fine team we make

So to sum up for the OP

Saline water has a lower freezing point but no additional ability to store thermal energy, as such, 2kg of non saline ice and 2kg of saline ice both at the same starting temperature (ie frozen in the same freezer for the same amount of time) should take the same amount of warm beer and time to bring the entire mix up to say 5 degrees.

There may be some minor variances such as if you take beer out along the way, for example as the ice slurry will be colder it may cause the beer to part freeze so when you remove a beer you will be removing a greater amount of thermal energy than if you remove a beer from the non saline esky.  Removing a greater amount of cold thermal energy each time in this manner will actually make the saline esky come up to the higher temperature quicker than the non saline.

To right Burnsy

[Jeepers Creepers]

The freezer in the shed must be ok.

All 3 two litre bottles are frozen like a rock. So i'll chuck the drinks in around them, then some party ice to take up the gaps.
I've kept the salted ice in bottles so it won't effect anything that might get put in the esky.

The forecast for tomorrow is 29 degrees, so once the campsite is set up, we can both sit back and enjoy a coldie.... or 4.

Only one more sleep now, by this time tomorrow (5:30am) we'll be starting off on the big haul (1/2 an hour) to Inskip Pt.

Anyway, it will be interesting to see how some party ice lives, however, i'll bung it in the freezer overnight to get it frozen.
Those party ice fridges are only a hair off having cold water from ice.

[LB]

Appologies if someone has already answered this. How much salt do you add?

Plus we used to freeze 2 ltr bottle but found that 2 ltr ice cream containers took longer to melt (have come home from a 5 day camp and still had ice in our tropical Ice box). We put a freezer bag in the ice cream container then the water. Every couple of days leading up to a camp we take the freezer bags out put it back in the freezer then do it all again. Before putting them in the esky we triple freezer bag so they don't leak.

LB