"evaporation" news and stories

Of all the households in the US, 99.5% have refrigerators. About the same percentage have some way of heating food. We've seen some great gadgets for keeping things hot and cold here on Slashfood, but I want to show you an ancient technique for keeping food cool. It's called a zeer pot. The vessel itself may be third world, but it's playing a timely role in the continuing recovery of northern Darfur and other African nations. Science in Africa magazine states that a zeer can keep tomatoes edible for 20 days, as opposed to two, and meat two weeks, as opposed to a few hours.

A zeer pot is quite simple. It's basically two large earthen pots, one nested in the other. The space is filled with sand and water is added. A damp cloth covers the top. As the water evaporates, the inner pot containing the perishables is kept cool in the same manner that a mechanical refrigerator operates -- water evaporation draws heat from the inner vessel. Water is added twice a day.

Muhammed Bah Abba is credited with reviving (some say inventing) use of the zeer and has his own instructions on theory, application and making one. I am going to make one of these myself and see how long basic vegetables will keep at room temp. You can see from the picture how easy it would be to improvise a zeer with regular flower pots. I will then give it a taste test after one week.

Source

No, it's not just to cool yourself. Our friends over at Engadget recently posted about the new Instant Cool Can from Tempra, a can with a built in cooling system that can drop the temperature of a beverage by 30º F in only a few minutes. The obvious application is beer, and according to Engadget, Miller will be the first to use the cans. The base of the can contains a drying agent that, when activated, causes a gel in the base to draw heat from the can into a heat sink. There's a lot is going on in the bottom half of this can, which explains why it looks like a 16 ounce can but only holds about 10.5 ounces. Obviously these cans will be more expensive, and for only 10.5 ounces of beer, it seems like smaller "pony" bottles are still the way to go if you want your cold one to stay that way until the end. Besides, I don't think anyone really cares what temperature "the champagne of beers" is served at anyway.