We love coffee as it cools. When it's at its sweet spot, which we believe to be around 135-150 degrees, the sweetness, acidity and mouthfeel are at their most balanced and beautiful. So when we found out about Coffee Joulies, a new product designed to keep coffee hot for up to five hours, we were slightly dubious…until we suspended our disbelief and took these Joulies for a showroom floor test run.

Coffee Joulies are coffee bean shaped, Cadbury Egg sized, nickel plated copper (and now stainless steel) doo-dads designed for dropping directly into your cup of coffee. Joulies contain an interior mystery material that melts and absorbs energy from the heat of the coffee, and using the laws of thermodynamics (or something), the inner goo stays warm as the coffee cools, effectively slowing down the cooling process.

We ran into the Joulies inventors Dave and Dave at the SCAA Expo kick-off party. Team Joulies first came to our attention via their Kickstarter campaign, which was an incredible success story that's earned more than $302,000 for their project as of the publication of this story. The Joulies project also went viral within the specialty coffee community, drawing equal doses of scorn and wonder. We were shocked when Dave and Dave told us that nobody in specialty coffee had actually tried these things out yet, so we decided to change that.

Armed with a sack of Joulies on Sunday, we headed to the Visions Espresso Supply booth and got to work. We had a limited amount of time to experiment, and the only thing we wanted to know was how the Joulies impacted the coffee's flavor.

Our Materials:

Hario V60 Ceramic Dripper
Hario V60 Paper Filter (prewet)
Digital Thermometer
Timer
Kettle
Scale
11oz glass

We brewed the Hario V60 using twenty grams of coffee and three hundred milliliters of water at around 200 degrees. 30 second bloom, 2:00 total pour, 2:45 brew time. We added three Coffee Joulies to the ten ounce cup of coffee and watched as the thermometer slowly crept down. When the coffee had finished brewing through the V60 it reached a temperature of around 155 degrees – totally drinkable and absolutely delicious. The coffee went down in temperature and hit 140 degrees at around five minutes, staying there for quite some time.

The coffee had a pleasant acidity, silky mouthfeel and fruit notes with a sweet finish – and absolutely no metallic taste whatsoever. The Joulies didn't result in a coffee that stayed hot hot hot, but rather, they seem to have extended that sweet spot (135-150 degrees) for a much longer time than the laws of thermodynamics would naturally allow. Co-founder Dave Petrillo knew that beverages near 140 degrees were generally accepted as a very pleasant “comfort zone”, but was unaware of the coffee sweet spot – and understandably excited with our results.

To some, this product is an answer to a question nobody asked. But in a very real way, it could be a revolutionary accident. This might even change the way we cup and evaluate coffee. One thing is certain: lengthening the enjoyment of an excellent cup of coffee is a very good thing.

Admittedly, a quick showroom floor evaluation isn't ideal, but it's made us Joulies believers. All the coffee geeks out there who might be skeptical should take a look at what their cupping spoons are made of.

Find out more about Coffee Joulies here.