
Coffee Joulies are stainless steel coffee beans with a special phase change metal inside of them. 'Phase change' just means that it's a metal that goes from solid to liquid and back again, but doing that is a lot of work, and the metal sucks up a substantial amount of heat when it melts. This means that when you drop one of these beans into hot coffee, the bean's insides will melt and the coffee will get cooler.

Coffee Joulies are currently on Kickstarter and have unsurprisingly blown way past their funding goal, but there's still plenty of time to pre-order a set of five beans for $40.