They’re oversized, shiny stainless-steel coffee beans and they’re being promoted for their ability to keep your beloved mug of coffee at the optimum temperature for twice as long. Coffee Joulies are the brainchild of two mechanical engineers, both named Dave, who are striving to perfect and lengthen the enjoyment of a cup of coffee. It’s a noble cause, but what exactly are Joulies and how do they work?

If Coffee Joulies work as well as their creators say they do, then essentially these stainless steel beans are the perfect remedy for those who regularly scald their mouth on hot coffee, as well as those who often end up drinking tepid coffee due to it being left to stand too long. But how?

The Science Behind the Joulie Bean

Coffee Joulies are made of the highest grade stainless steel, but inside they are filled with Phase Change Material (PCM) which melts at 140°F and is 100% edible. When you drop these seemingly magic Joulies into your hot cup of java, the PCM inside the stainless steel bean changes from a solid to a liquid and absorbs excess heat. This phase change takes place at around 140°F, which also happens to be just about the perfect drinking temperature. But wait, there’s more. As your coffee starts to cool, the PCM inside the Joulies starts to solidify and releases its heat – thereby keeping your coffee warmer for longer!

The Origin of Coffee Joulies

It sounds awesome! And although they’re being marketed to coffee lovers, in theory, Coffee Joulies should work in any hot drink. So where can you get your hands on these jolly Joulies? Well, Dave and Dave began the Coffee Joulie project on Kickstarter, which is an online pledge system for funding creative projects. They sought $9500 in funding, but in the end they raised $306, 944 to back their project. They received 8000 pre-orders through Kickstarter which they are now working full-time to fulfil.

What’s the Verdict So Far?

Many early pledgers have already received their Coffee Joulies and, while some have praised the two Daves for their invention, others are not convinced. Some reviews claim that Coffee Joulies only work well in conjunction with a thermo flask, and that they take up 15% of the volume of a coffee cup.

Coffee Joulies are likely to just be novelty items that come in a cute little bag, but hey, I’d still give them a try. After all, I’ve gulped down many a cold cup of coffee in my life – too many I say! Hopefully Coffee Joulies will come to South Africa soon so we can put them to the test.

What do you make of these shiny beans? Would you try them?