SWMBO bought the pictured carafe because it was locally made and rather pretty. To our surprise, it keeps water about ten degrees (estimate) cooler than ambient temperature.

I mean, you can fill it with water that is 20 degrees warmer than ambient, and by the next morning it will be 10 degrees cooler, just sitting on the nightstand.

A little bit of crude testing suggests a possible reason for this phenomenon. I put it in the kitchen sink and filled it absolutely to the top of the spout, then covered the spout. After several hours, the water level had dropped by about an inch.

My hypothesis is that the material the carafe is made from acts something like GoreTex, and allows water to pass through it cooling the contents at a rate of 540 calories for each gram of water that evaporates. The outside of the carafe feels dry with no hint of moisture, and is startlingly cool to the touch.

Does this seem reasonable?

tanstaafl.