See those shiny metal beans? They’re hungry. They LOVE heat. They want to eat up all the extra thermal energy that makes coffee too hot so you can drink it sooner without burning your tongue.
How do they do that? Their polished stainless steel shells are full of a very special phase change material (an ingredient in food) that melts at 140°F. When you put them in your coffee this PCM begins melting, absorbing a LOT of heat in the process and cooling your coffee down much faster than normal.
Where does all that heat go? It’s stored right inside your Coffee Joulies™. When your coffee reaches 140°F (the perfect drinking temperature) the molten PCM begins solidifying again, releasing all that energy back into your coffee to keep it at a comfortable and delicious drinking temperature. The more heat you feed your Joulies, the longer they’ll keep your coffee warm.