If you need to keep food/drinks cold (but not frozen) for an extended period, like for camping or a road trip, dry ice can be used to convert a cooler into a refrigerator! Dry ice is a no-mess, clean way to refrigerate goods. It keeps food/drink colder than regular ice, for longer, and it doesn't leave behind a wet, watery mess like regular ice will. Dry ice "sublimates" which means it evaporates into thin air. It's a great solution for road trips, camping, Burning Man camps, and more.
The exact temperature of your cooler (now a dry ice refrigerator) will depend on the amount of dry ice you use, the size of your cooler, and amount of food/drink inside the cooler. Dry ice comes in either blocks or pellets.
For this project you will need dry ice blocks. To get an estimate of how much dry ice to buy for your dry ice fridge, depending on your cooler size and the number of days you'll be using it use our Cooler Calculator.
Always handle dry ice with care and wear gloves whenever touching it. An oven mitt or towel will also work if gloves are not handy. If touched briefly, dry ice is harmless, but prolonged contact with the skin will cause injury similar to a burn.
Find more safety information on our dry ice safety page.
Wrap dry ice blocks in newspaper. This insulates the dry ice blocks, which slows down the speed at which they sublimate into air. If you don’t have a newspaper on hand, you can also wrap the blocks in a towels or with rags, but newspaper is often wraps the blocks more easily. Wrap the blocks fairly tightly to protect them from air.
Place the wrapped blocks on the bottom of your cooler. For a regular 60-90 quart cooler (the typical cooler you’d take camping), you’ll be able to fit two dry ice blocks side by side along the bottom.
On top of these wrapped blocks, you can put a layer of insulation like newspaper, a towel, or a piece of cardboard. It’s best to keep this layer of insulation thin so that the cold air from the dry ice can get through to food. The reason for this optional insulation is to protect any more fragile perishable items like fruits and vegetables, which will get freezer burn if they’re too close to the dry ice. Feel free to skip this step if you are not worried about fragile items.
Add your food/drinks to the cooler. Remember that the items closest to the dry ice will be coldest, so it’s good to pack the cooler strategically.
Each wrapped dry ice block will last 24-36 hours. The more you keep the cooler closed, the longer they will last. If you need to use your refrigerator for more than 36 hours, replace the wrapped dry ice blocks with new blocks.