keeping food frozen

[ness]

last yr I took a colman xtreme cooler , put in a block of ice, and then our meat and some icecream covered it all with cube ice and then 3 handfulls of rock salt the ice cream lasted for 3 days in great shape and the meat stayed good for 8 days. I also salted my beer cooler and it froze the beer on top.

[BAS]

Which Coleman Xtreme did you use? I seem to recall that there are at least two different ones. Just curious.

[Stormy]

Just a tip to anyone who hasn't tried an "extreme" cooler before, beware of the ones with plastic latches. I've heard they can break off.

[SealBoy]

Another option is dry ice, as big a block as possible in an airtight cooler so it lasts all week. Two big perks of this method:
1. Ice cream sandwiches on Friday, and
2. Not having to stand in the ice line ever again (bring some ice cube trays)

Solid CO2 does evaporate fast, so it's important to have a big block. Also, anything touching the block will get burned badly (including ice cream).

This year I'm working on a liquid nitrogen-cooled freezer system!

SealBoy.

[Stormy]

This year I'm working on a liquid nitrogen-cooled freezer system!

Oooh, please keep us posted on this!

[nollij]

So... remind me again.... the rock salt needs to go on TOP of the ice, right? Does this really work? I know you use rock salt somehow to MAKE ice cream in those old fashioned ice cream makers, but I can't for the life of me remember how the hell this works...

last yr I took a colman xtreme cooler , put in a block of ice, and then our meat and some icecream covered it all with cube ice and then 3 handfulls of rock salt the ice cream lasted for 3 days in great shape and the meat stayed good for 8 days. I also salted my beer cooler and it froze the beer on top.

[SealBoy]

So... remind me again.... the rock salt needs to go on TOP of the ice, right? Does this really work? I know you use rock salt somehow to MAKE ice cream in those old fashioned ice cream makers, but I can't for the life of me remember how the hell this works...

Two things make this work:
1. Dissolution of salt in water is an endothermic reaction (i.e. it pulls heat out of the water)
2. Salty water has a lower freezing point than pure water

So when you add rock salt to an ice water mixture, it initially cools the water by dissolving, causing the ice to melt more slowly. Then the salty water can cool to a temperature below the normal 32 degree melting point, again keeping the ice from melting. The salt should be spread evenly on the melting ice surface and in the surrounding water to maximize your cooling power.

This phenomenon is well-studied in the seal community, particularly by our Alaskan colleagues.

SealBoy.

[Icepack]

So... remind me again.... the rock salt needs to go on TOP of the ice, right? Does this really work? I know you use rock salt somehow to MAKE ice cream in those old fashioned ice cream makers, but I can't for the life of me remember how the hell this works...

Two things make this work:
1. Dissolution of salt in water is an endothermic reaction (i.e. it pulls heat out of the water)
2. Salty water has a lower freezing point than pure water

So when you add rock salt to an ice water mixture, it initially cools the water by dissolving, causing the ice to melt more slowly. Then the salty water can cool to a temperature below the normal 32 degree melting point, again keeping the ice from melting. The salt should be spread evenly on the melting ice surface and in the surrounding water to maximize your cooling power.

This phenomenon is well-studied in the seal community, particularly by our Alaskan colleagues.

SealBoy.

Yet another reason why I should have taken Chemistry.... I am confused. I thought rock salt was what they use to MELT the snow and ice on the roads in winter. And now you all are talking about using it to make better ice. You would think with a name like Icepack, I would understand this, but sadly the mists of confusion are clouding over my foggy brain.

[Isotopia]

Keeping food frozen?

Here hon, just set your groceries next to my cold, cold heart.

[SealBoy]

Yet another reason why I should have taken Chemistry.... I am confused. I thought rock salt was what they use to MELT the snow and ice on the roads in winter. And now you all are talking about using it to make better ice. You would think with a name like Icepack, I would understand this, but sadly the mists of confusion are clouding over my foggy brain.

Hmmm... good question. The main thing salt does is LOWER the freezing temperature of water. That is, pure water freezes at 32 degrees Farenheit (0C), but salt water freezes at, say 20 degrees Farenheit (-6C). So spreading salt on the ice-covered sidewalk lowers the melting point, and allows the water to turn to liquid in "sub-freezing" temperatures. If it's 23 degrees outside and you throw a bunch of salt on your driveway, the ice will eventually melt as the salt gets absorbed. Without the salt, the ice would never have melted in that cold air!

So how the heck does salt keep my cooler ice from melting?!? Well, it doesn't necessarily, but it lowers the temperature of any surrounding water below 32 degrees Farenheit. Since dissolving salt takes energy out of the water (i.e. an "endothermic reaction"), this lowers the water temperature. If any ice melts, it must absorb heat, which again lowers temperatures. Your ice is now in contact with 20-degree water, making it less likely to melt. And the air in the cooler stays cold.

Now, contrary to my previous post, I'm not sure that salt will keep the ice block from melting. But it will certainly take heat out of the air and food, which is what you're shooting for. Sogginess might be a factor to consider.

This seal will perform an experiment to see whether salt extends or shortens the ice block's life, and how cooler temperatures are affected. I'll post the results here.

SealBoy out.

[_tears_]

I have never heard of these nifty coolers, are they REALLY worth it?

It sounds like it to me -- but i have never used them.

Just wondering If you did BOTH methods, the Dry ice AND these "extreme coolers" would it work better?

[Stormy]

I have never heard of these nifty coolers, are they REALLY worth it?

It sounds like it to me -- but i have never used them.

Just wondering If you did BOTH methods, the Dry ice AND these "extreme coolers" would it work better?

That's my plan for this year.

[EB]

I have never heard of these nifty coolers, are they REALLY worth it?

Very much so.

After five days, the ice in the brand X coolers had long since melted but the Coleman Extreme was STILL going strong. But the tradeoff is space. The Extremes are REALLY tiny, so we used it for important stuff like meat.

Also: Don't know if you do this trick, but freezing a bunch of juice boxes and Capri Suns and using them instead of those Blue Ice things (and regular ice, for that matter) really worked for us.

Since they're mostly water anyway, they work just as well as ice. Then, when they melt, you drink 'em which then frees up room in the cooler for an ice block from Camp Arctica (block ice gives you more bang for your buck than ice cubes.)

Best of all, there's less disgusting cooler water to haul back/evaporate/mist.

EB

[EB]

Keeping food frozen?

Here hon, just set your groceries next to my cold, cold heart.

If I had been drinking milk when I read this, it would've gone up my nose.

[precipitate]

Jeebus.

Use dry ice to keep things rock-solid frozen for multiple days. Number of
days depends on the quality of your cooler. The Coleman Xtreme coolers
are lovely. As are the Coleman stainless.

Use an ice-water slurry to apply maximum cooling to the contents of your
cooler. But expect to have to replenish the ice bit regularly.

You could use salt, but it only reduces the freezing point by a couple of
degrees, and in the long term (more than a day or so) probably isn't
worth much.

Above all, make sure that the stuff you put in your cooler is water-tight.
Nothing worse than baloney water on day 1.

[_tears_]

I had a friend who did the juice box thing, and around 50% of them popped/broke open.

[Selkie]

I had a friend who did the juice box thing, and around 50% of them popped/broke open.

It's probably because those boxes aren't meant to hold up to the expanding and contracting of freezing and then warming up. I'd recommend just lots of frozen water bottles. I do this at work all the time so I always have cold water at my desk and I have yet to ever have one pop on me.

Besides, what could possibly be more wonderful than ice cold water on your third or fourth day there?

[safetythird]

Would wrapping my cheapo coolers in sleeping bags and space blankets bring up the insulation to Xtreme levels? As I prepare for BM I'm finding less and less money for things like new coolers and I'd prefer to recycle what I already own.


Safety Third!

[Stormy]

Would wrapping my cheapo coolers in sleeping bags and space blankets bring up the insulation to Xtreme levels? As I prepare for BM I'm finding less and less money for things like new coolers and I'd prefer to recycle what I already own.


Safety Third!

Well it won't make ice last for five days, but it should last 3 days instead of one. I assume you're also going to put it up on milkcrates or keep it off the ground some way?

[EB]

I had a friend who did the juice box thing, and around 50% of them popped/broke open.

Hm. Come to think of it, I used Capri Suns. I didn't have a problem with them busting open. Maybe their packaging has a little more give.

[MMadeleine]

I was thinking about getting big bottles of juice (approx 1.75L in plastic bottles) and freezing them to use as block ice in the coolers, then drink as they melt. Since water expands as it converts to ice, should I be doing anything special to prevent the bottles from breaking? Has anyone done this before? Is the plastic generally sturdy enough to hold? Any suggestions would be appreciated - thanks!

[phil]

I was thinking about getting big bottles of juice

Works for Louise and me. They don't stay frozen the whole time, of course.

[theCryptofishist]

I think that that half inch at the top may be enough. Try it with one and see.

[AntiM]

If you're coming from sea level, I do know some things swell up and poop. Lotion bottles are notorious, when larry's on the truck he squeezes the air out of everything that has a lid when he's in California so nothing explodes when he hits higher altitudes. He has a candle in a jar with an aluminum lid; you can hear it "pop" when we go up and down mountains.

Never experimented with freezing AND changing altitudes however ... anyone?

[theCryptofishist]

Hadn't thought of that. I'm guessing that when it's solid it doesn't make much difference. If you pour off a little bit of the juice as it begins to melt... Or you could open the seal and pour off more, i guess.

[phil]

Would wrapping my cheapo coolers in sleeping bags and space blankets bring up the insulation to Xtreme levels? As I prepare for BM I'm finding less and less money for things like new coolers and I'd prefer to recycle what I already own.

I tried a space blanket one year. I got condensation on the inside of the space blanket, which made the blanket and the ice chest playa powder magnets, and I wasn't satisfied that it made anything last longer enough to be worth the aggravation of keeping it wrapped. Your mileage will vary. I've pretty much tried all the urban legends: styrofoam in the chest, styrofoam outside the chest (it shreds), keeping the cooler up off the ground a couple of inches, taping it shut, space blanket.

We finally broke down and bought a Coleman Xtreme, and it worked so much better we bought another one. They're more expensive, and I understand the hesitation, especially if you only use them once a year, and the recycling issue. If your ice lasts long enough, then stick with what you've got. If not, try space blankets and such and see if you can get it to work for you. Some people swear by it.

[AntiM]

I found padded, quilted fabric, the thin stuff used to make placemats or evening jackets, and sewed up fitted slipcovers. Then we throw our extra blanket ponchos on top, but mostly to have a place to throw the ponchos. Works like a charm. I guess the fabric absorbs the condensation and wicks it off.

That was our first year, I kept thinking we were "Camp It's a Good Thing." I even had a dust ruffle and throw pillows for the cot and velvet curtains to drape around the U-haul. Heh. We even brought the full-size propane grill that year.