Q. We're planning a trip to Ocracoke, about an eight-hour drive. I've heard grocery shopping is limited, so I'd like to take precooked, frozen foods in a cooler. Should I pack the cooler with dry ice? I've never used dry ice and most Web sites don't make it sound safe or easy.
If the food is frozen or well-chilled when it goes into the cooler and you use plenty of ice, it should be fine. Some of the ice will melt, but ice water actually is colder than ice alone. You also can wrap a blanket or thick towel around the cooler to further insulate it.
Dry ice is only essential for transporting things like ice cream that are frozen at temperatures close to 0. For something like that, ice (which freezes below 32 degrees) actually is warmer than the food itself, so ice cream will melt faster if you try to transport it with ice.
But for future reference, dry ice isn't difficult to handle. You can buy it at many supermarkets these days. Make sure you don't handle it with bare hands – it's so cold, it can “burn” your skin – but you can wrap it in a brown paper bag so you don't have to touch it. It dissolves very slowly in a cooler (it doesn't actually melt, it converts back to a gas). You wouldn't want to leave an open cooler of dry ice in a small, enclosed space like a car for very long, but opening and closing the cooler a few times on a trip isn't a problem.
The best part is having dry ice to play with when you're finished. If there are any kids around, throw a chunk of leftover dry ice into a sink of hot water – it bubbles a lot more than if you put it in cold water.