Calling all experts in ice cream and heat transfer
August 17, 2015 12:29 PM Subscribe
Bringing homemade ice cream to a beach bbq/picnic, limited resources for cooling/storage: am I setting myself up for sad melty disappointment?
To be transported:
Two pints of ice cream, frozen in glass containers
Packing materials on hand:
1 small soft-sided cooler/lunch bag
2 ice packs (small-ish)
Various insulating materials (neoprene sheets, regular towels, etc) if helpful
The ice cream and ice packs will be taken from the freezer, onto the bus for about 30 minutes to the beach, where it will sit for probably another 1.5 - 2 hours before being served. Weather looks like it will start at around 77F/25C and cool down through the evening. Am I going to have nice scoopable ice cream, or will it be a sad, soupy mess by the time we're ready to dig in?
To be transported:
Two pints of ice cream, frozen in glass containers
Packing materials on hand:
1 small soft-sided cooler/lunch bag
2 ice packs (small-ish)
Various insulating materials (neoprene sheets, regular towels, etc) if helpful
The ice cream and ice packs will be taken from the freezer, onto the bus for about 30 minutes to the beach, where it will sit for probably another 1.5 - 2 hours before being served. Weather looks like it will start at around 77F/25C and cool down through the evening. Am I going to have nice scoopable ice cream, or will it be a sad, soupy mess by the time we're ready to dig in?
If there's no shade, consider constructing a makeshift radiant barrier above, but not touching, the cooler. Could be as simple as a towel resting on four sticks stuck in the sand. A reflective material, like aluminium foil, would work even better.
posted by JackBurden at 12:45 PM on August 17, 2015
posted by JackBurden at 12:45 PM on August 17, 2015
Find some dry ice. I knew a guy that would bring ice cream on summer hiking trips and he would always pack it inside dry ice.
It's pretty easy to get your hands on
Don't literally put your hands on it, however. Use tongs or gloves.
posted by bondcliff at 12:55 PM on August 17, 2015 [3 favorites]
It's pretty easy to get your hands on
Don't literally put your hands on it, however. Use tongs or gloves.
posted by bondcliff at 12:55 PM on August 17, 2015 [3 favorites]
Dry ice in a Styrofoam box will be ideal.
posted by Everydayville at 1:11 PM on August 17, 2015
posted by Everydayville at 1:11 PM on August 17, 2015
Soupy mess. I tried this with popsicles. If you don't go the dry ice route freeze flat blocks of ice by half filling ziploc sandwich bags with water and freezing them flat. Use liberally and don't open the cooler until you're ready to serve. Also, keep the cooler in the shade.
posted by irisclara at 1:13 PM on August 17, 2015 [2 favorites]
posted by irisclara at 1:13 PM on August 17, 2015 [2 favorites]
Response by poster: Aw man, this is not good news -- dry ice is a little more inconvenient to procure here than it is in the US so it would be logistically difficult for me to run around getting things ready in time. Maybe I'll save the ice cream for another time and just go grab some beers..
posted by btfreek at 1:23 PM on August 17, 2015 [4 favorites]
posted by btfreek at 1:23 PM on August 17, 2015 [4 favorites]
Microclimates are your friend.
Pre-cool containers etc. Make sure everything is as cold as you can get it before you stick the ice cream in it.
Find a cool, shady spot to put the cooler in.
And so on.
Also, digging a pit and sticking the cooler in wet sand might go a long ways towards keeping things cool. This is a principle used to make non-electric "refrigerated" storage.
But if you don't have experience doing that ahead of time, you may not be able to pull it off. Cold beers might be the better answer this trip.
posted by Michele in California at 1:57 PM on August 17, 2015
Pre-cool containers etc. Make sure everything is as cold as you can get it before you stick the ice cream in it.
Find a cool, shady spot to put the cooler in.
And so on.
Also, digging a pit and sticking the cooler in wet sand might go a long ways towards keeping things cool. This is a principle used to make non-electric "refrigerated" storage.
But if you don't have experience doing that ahead of time, you may not be able to pull it off. Cold beers might be the better answer this trip.
posted by Michele in California at 1:57 PM on August 17, 2015
Have a look at a Zeer Pot fridge. They're cheap to assemble and work reasonably well if the humidity is low in your area.
posted by Solomon at 2:11 PM on August 17, 2015 [1 favorite]
posted by Solomon at 2:11 PM on August 17, 2015 [1 favorite]
I think salt water ice gets colder, stays colder. So freeze it in the bottom of the cooler, if you can stick a couple of forms in the brine so the ice cream is encased. Line it with strong plastic, put regular cubes on top, bubble wrap the cooler, 'til it is time. Put the ice cream in the hollows you form, don't use the real ice cream container to make the space. Have a nice day.
posted by Oyéah at 2:38 PM on August 17, 2015
posted by Oyéah at 2:38 PM on August 17, 2015
Try salt ice. Freeze salty water in soda bottles, probably need to crank up the freezer settings. But salt water is what froze home made anyway.
Also what worked well is a cooler in a cooler. I happened to have an ok/good hard cooler that fit in one of the soft ones.
Add layers of extra insulation: blankets.
Actually a space blanket wrapping a cooler with extra blankets around it should keep pretty cold.
One of those foldable car window reflector shades on top wouldn't hurt.
posted by sammyo at 2:51 PM on August 17, 2015
Also what worked well is a cooler in a cooler. I happened to have an ok/good hard cooler that fit in one of the soft ones.
Add layers of extra insulation: blankets.
Actually a space blanket wrapping a cooler with extra blankets around it should keep pretty cold.
One of those foldable car window reflector shades on top wouldn't hurt.
posted by sammyo at 2:51 PM on August 17, 2015
Best answer: Yeah, basically ice cream melts at a colder temperature than water melts, and the ideal serving temperature for ice cream is about -10°C.
When you pack stuff with ice to keep it cold, the temperature will fairly rapidly rise until it reaches the melting point of the ice, because melting ice absorbs a lot more energy than temperature changes that don't cross over the melting point (e.g., -4 to -3 degrees). So you want to pack it with ice that melts at -12C. Sammyo's ice water suggestion is certainly the easiest way to do this. The freezing of salt water varies with salinity and you can see that for -10C you need about 150g of salt per kilogram (liter) of fresh water.
Note that 1L of water + 150g of salt will be a little larger than 1L, so you can't just take a 1L soda bottle, put 150mg of salt in it, and fill it up with water. Measure and mix separately, and then fill and freeze your bottles. I'd maybe squeeze the bottles a bit when closing them so there's room for the ice to expand without causing a messy explosion in your freezer. Expect these to take a long time to freeze, even with your freezer turned to its maximum coldness.
For just a couple hours I don't think you'll need to do anything fancy with multiple layers of coolers or whatever. But if your soft-sided cooler has thinner walls, you can increase its effectiveness by reducing air flow on either side of those walls, by putting everything in a plastic bag before putting it in the cooler, and putting the whole cooler in another plastic bag. Wrapping it in a blanket (or sweater) will help, and of course keep it in the shade.
Burrying it under wet sand will be counterproductive - it will help keep it the temperature of wet sand, which is cool but not cold. Instead you're trying to isolate it from things warmer than it. Of course, be sure to keep it in the shade.
posted by aubilenon at 3:21 PM on August 17, 2015 [4 favorites]
When you pack stuff with ice to keep it cold, the temperature will fairly rapidly rise until it reaches the melting point of the ice, because melting ice absorbs a lot more energy than temperature changes that don't cross over the melting point (e.g., -4 to -3 degrees). So you want to pack it with ice that melts at -12C. Sammyo's ice water suggestion is certainly the easiest way to do this. The freezing of salt water varies with salinity and you can see that for -10C you need about 150g of salt per kilogram (liter) of fresh water.
Note that 1L of water + 150g of salt will be a little larger than 1L, so you can't just take a 1L soda bottle, put 150mg of salt in it, and fill it up with water. Measure and mix separately, and then fill and freeze your bottles. I'd maybe squeeze the bottles a bit when closing them so there's room for the ice to expand without causing a messy explosion in your freezer. Expect these to take a long time to freeze, even with your freezer turned to its maximum coldness.
For just a couple hours I don't think you'll need to do anything fancy with multiple layers of coolers or whatever. But if your soft-sided cooler has thinner walls, you can increase its effectiveness by reducing air flow on either side of those walls, by putting everything in a plastic bag before putting it in the cooler, and putting the whole cooler in another plastic bag. Wrapping it in a blanket (or sweater) will help, and of course keep it in the shade.
Burrying it under wet sand will be counterproductive - it will help keep it the temperature of wet sand, which is cool but not cold. Instead you're trying to isolate it from things warmer than it. Of course, be sure to keep it in the shade.
posted by aubilenon at 3:21 PM on August 17, 2015 [4 favorites]
I have some experience hauling homemade ice cream around, and keep in mind it often melts faster than store-purchased ice cream depending on how long it's been ripening in the freezer. I would say if you could cajole people to eat it more or less right away it would probably be OK, but otherwise it's probably not worth the trouble. However, anyone with a brain in their head should not require much cajoling to eat homemade ice cream right away. My ice cream eating services are available any time.
posted by rafaella gabriela sarsaparilla at 4:17 PM on August 17, 2015 [1 favorite]
posted by rafaella gabriela sarsaparilla at 4:17 PM on August 17, 2015 [1 favorite]
One thing you can do is turn the freezer down so everything starts out as cold as you can get it.
posted by theora55 at 1:01 PM on August 18, 2015
posted by theora55 at 1:01 PM on August 18, 2015
This thread is closed to new comments.
posted by goingonit at 12:33 PM on August 17, 2015 [6 favorites]