How much dry ice for ice cream
Plan the dry ice for a cooler of ice cream, or see how long regular ice will hold it firm.
This calculator answers two questions: how much dry ice to buy to keep ice cream frozen in a cooler, and how long regular ice will hold it. It is for hosts carrying ice cream to a party, picnic or event, and for anyone driving a few pints home from a store far away.
The numbers under the calculator are a worked example with the default inputs. They update as soon as you change the cooler size, hours, air temperature or cooler build.
Dry Ice and Cooler Calculator
Dry ice to buy
5 to 10 lb
of dry ice (2.3 to 4.5 kg) for 18 hours in a 60 quart standard hard cooler at 85°F
How the amount adds up
- Rate per 24 h
- 5 to 10 lb
- supplier figure
- Size factor
- × 1.16
- 60 qt vs 48 qt
- Heat factor
- × 1.08
- 85°F vs 70°F
- Sun or hot car
- × 1.0
- not included
About 4.7 to 9.4 lb turns to gas over 18 hours. We round up to whole pounds.
Buy the high end when in doubt, and buy it as close to the time you need it as you can. Wear gloves and keep the cooler lid unsealed and the car ventilated.
With regular ice
Use dry ice
18 hours with plain ice. Our rough planning range for firm ice cream: 1 to 2 hours.
What it means
Your hours run past our planning range for regular ice. Use dry ice or keep the ice cream in a freezer until serving.
In a test by America's Test Kitchen, four half gallons packed with 5 pounds of regular ice in a midsize cooler were soupy after 3 hours; with dry ice it took 9 hours.
Buy 5 to 10 lb of dry ice. Use dry ice: 18 hours with plain ice.
How the dry ice math works
Dry ice = rate per 24 h × hours ÷ 24 × size × heat × sun
Size = (quarts ÷ 48) to the 2/3 power, 0.5 to 2.5
Heat = (°F + 109.3) ÷ (70 + 109.3)
Buy = rounded up to whole pounds, at least 5 lb
The calculator starts with a rate: how many pounds of dry ice turn to gas in one cooler over 24 hours. Those rates come from suppliers, DryiceInfo and WestAir, and depend on how the cooler is built. A standard hard cooler loses 5 to 10 pounds a day at about 70°F. We multiply the rate by your hours and divide by 24.
Everything after that is our own planning model. The size factor is our assumption: we treat the published rates as describing a 48 quart chest, then scale by your cooler’s quarts over 48, raised to the 2/3 power, because a bigger cooler has more wall for heat to leak through. The temperature factor is your air temperature plus 109.3, divided by 70 plus 109.3. That uses WestAir’s figures for dry ice (-109.3°F) and for the rate (about 70°F), and the University of Guelph’s point that heat flows in with the temperature difference. A cooler in sun or a hot car gets 30% more, following WestAir.
Take the default example: a 60 quart standard hard cooler, 18 hours, 85°F, in the shade. The size factor is 1.16 and the temperature factor is 1.08, so about 4.7 to 9.4 pounds turns to gas. We round up to whole pounds and never go under WestAir’s 5 pound minimum, so you buy 5 to 10 pounds (2.3 to 4.5 kg). Buy the high end when in doubt.
In regular ice mode, the calculator compares your hours with our rough ranges: 1 to 2 hours for plain ice, 2 to 4 with rock salt. Inside the low end, ice will do. In between, it is tight. Past the high end, use dry ice.
Supplier rates by cooler
| Cooler | Per 24 h | Source |
|---|---|---|
| Thin-walled or soft cooler | 10 to 15 lb | DryiceInfo, Safety: depending on the insulation, dry ice sublimes 10 to 15 pounds every 24 hours |
| Standard hard cooler | 5 to 10 lb | DryiceInfo: 5 to 10 pounds per day in a standard insulated cooler; WestAir: 5 to 10 pounds per 24 hours at room temperature (about 70°F) |
| Thick-walled premium cooler | 2.5 to 3.3 lb | WestAir: high-end coolers with 2 to 3 inch walls can stretch 10 pounds of dry ice to 3 to 4 days |
Heat factor by air temperature
| Air | 50°F | 60°F | 70°F | 80°F | 90°F | 100°F |
|---|---|---|---|---|---|---|
| Factor | × 0.89 | × 0.94 | × 1.00 | × 1.06 | × 1.11 | × 1.17 |
Regular ice, our rough planning ranges
| Packed with | Firm for about |
|---|---|
| Plain ice | 1 to 2 hours |
| Ice and rock salt | 2 to 4 hours |
America's Test Kitchen found ice cream packed with regular ice soupy after 3 hours. Brine: about 1 part rock salt to 10 parts crushed ice by weight (500 g salt to 5 kg ice).
Numbers the calculator uses
- A thin-walled or soft cooler loses 10 to 15 pounds of dry ice every 24 hours, according to DryiceInfo, a site run by dry ice sellers.
- A standard hard cooler loses 5 to 10 pounds of dry ice per 24 hours at about 70°F, a figure both DryiceInfo and WestAir give.
- A thick-walled premium cooler loses about 2.5 to 3.3 pounds per 24 hours, based on WestAir's note that 2 to 3 inch walls stretch 10 pounds to 3 to 4 days.
- Our planning assumption is that the published rates describe a 48 quart chest, so we scale by cooler quarts over 48, raised to the 2/3 power, kept between 0.5 and 2.5.
- The temperature factor uses dry ice at -109.3°F and the 70°F rate from WestAir, plus the University of Guelph's point that heat flows in with the temperature difference.
- We add 30% when the cooler sits in sun or a hot car, following WestAir's advice to pack about 30% more dry ice for summer heat.
- Our own rough planning ranges, not measurements, say plain ice keeps ice cream firm for about 1 to 2 hours, and ice with rock salt for about 2 to 4 hours.
Dry ice safety
- Dry ice is -109°F (-78°C), so wear insulated gloves; brief contact is harmless, but longer contact freezes skin like a burn.
- Never put dry ice in an airtight or sealed container, because the gas can make it burst.
- Use and store dry ice where air moves, since the carbon dioxide gas can push oxygen out of a closed space.
- Never ride in a closed car with dry ice, and keep air moving through the car for the whole drive.
- If dry ice has been in a closed car, van or room for over 15 minutes, air it out first, and leave if you get a headache or breathe hard.
- Do not keep dry ice in a working freezer, because it may shut the freezer down.
- Keep dry ice away from children and pets.
- Do not leave dry ice on tiled counters or floors, because the cold can crack them.
Packing the cooler
- Put the dry ice on top of the ice cream, because cold air sinks.
- Fill the empty space in the cooler, since dead air space makes dry ice turn to gas faster.
- Wrap the dry ice in newspaper to insulate it and make it last longer.
- Split pellets into paper bags to spread them out, and never seal plastic bags tight, or they will burst.
- Buy dry ice as close to the time you need it as you can, because it starts disappearing once made.
- Ice cream packed with dry ice can freeze very hard, so let it soften before scooping.
Questions people ask
How much dry ice do I need for ice cream?
For a 60 quart standard hard cooler over 18 hours at 85°F, out of the sun, plan on 5 to 10 pounds (2.3 to 4.5 kg). A bigger cooler, a longer trip, hotter air or a sunny spot raises the amount. Enter your own numbers above, and buy the high end of the range when in doubt.
How long will ice cream stay frozen in a cooler with regular ice?
Not long. America's Test Kitchen found that four half gallons packed with 5 pounds of regular ice in a midsize cooler turned soupy after 3 hours, while a similar cooler with dry ice took 9 hours. Our own rough planning range for plain ice is about 1 to 2 hours of firm ice cream.
Why can't regular ice keep ice cream hard?
Regular ice sits at about 32°F, the temperature where ice melts. The sugars in ice cream lower its freezing point below that, as the University of Guelph explains, so plain ice only slows the softening. Ice with rock salt, about 1 part salt to 10 parts ice by weight, makes a colder brine. Our rough range for it is about 2 to 4 hours.
Can I ride in the car with dry ice?
Not in a closed car. Dry ice turns to carbon dioxide gas, which can push oxygen out of a closed space, so keep air moving the whole drive. If it has sat in a closed car for more than 15 minutes, open the doors and let it air out before you get in. Leave if you start breathing hard or get a headache.
Why does a short trip still call for 5 pounds?
We never suggest less than 5 pounds, following WestAir's 5 pound minimum for overnight shipping. Dry ice starts disappearing as soon as it is made, and a 5 pound floor keeps a real layer over the ice cream even on a short drive home from the store.
Will dry ice make my ice cream too hard to scoop?
It can. Ice cream packed with dry ice can freeze very hard, so let it sit and soften before you scoop. When you arrive, keep the dry ice out of any working freezer, because it may shut the freezer down. Leave it in the cooler where air moves instead.
Sources
- All about dry ice (sublimation rate, storage) DryiceInfo
- Safety precautions for dry ice DryiceInfo
- Dry ice for camping (packing) DryiceInfo
- How Long Does Dry Ice Last? WestAir
- Chilling Food with Dry Ice vs. Regular Ice America's Test Kitchen
- Ice Cream Technology e-Book: Homemade Ice Cream (ice and salt brine) H. Douglas Goff, University of Guelph
- Ice Cream Technology e-Book: Hardening (heat transfer) H. Douglas Goff, University of Guelph
- Ice Cream Technology e-Book: Theoretical Aspects of the Freezing Process H. Douglas Goff, University of Guelph
Every data source the site uses is on the Sources page.