Dry Ice

[Bluegreen kayak]

Before putting cans or bottles of beverages in a cooler, chill them in a refrigerator. That way, you don't use up ice getting them cold. They are already cold.

Anyone thinking about dry ice should know that the temp is -109F. Handle carefully. If immersed in water, it bubbles away producing a fog of CO2 gas. Great for Halloween and special effects but probably not for keeping stuff cold.

The Halloween business is what prompted my question about putting dry ice in water. I was helping with such an activity at a historical site, and was carrying a bucket that was supposed to produce said fog from dry ice in water. Instead, the water around the ice kept freezing, and no fog came out. I had to very carefully break the dry ice over and over again to get anything. It made me wonder how long it would take the dry ice to disappear if it kept creating an frozen shield around itself.

My thanks to everyone for the great advice here. I have used water frozen in large rinsed-out juice bottles and it does work well. I would like something that lasts as long as possible.