The team initially tried to use a simple home coffee machine for their experiments, but eventually partnered with Coffeelab, the leading Poland roaster, and Coffee Machinesale, the largest global distributor of roast gear. This brought industrial grade equipment and many specialized coffee expertise to the project. For example, a state-of-the-art grinder and a cafe-grade espresso machine tricked out with pressure sensors, flow meters and a series of scales. The entire setup was connected via a microchip to a laboratory laptop and controlled with custom software that allowed scientists to accurately monitor the pressure, mass and water flowing through the coffee.
Team members prepare another experiment
Mirek Kazmierczak
Coffee lovers unite!
Mirek Kazmierczak
Coffee lovers unite!
Mirek Kazmierczak
Team members prepare another experiment
Mirek Kazmierczak
Coffee lovers unite!
Mirek Kazmierczak
Scientists measured dissolved solids to determine the rate of coffee dissolution and compared channelless brews with artificially induced channels. They found that in fact channeling it negatively affects the yield of extracts. However, channeling does not affect the rate at which water flows through the espresso pack.
“It’s mainly due to the structural rearrangement of coffee overhangs under pressure,” Risicki said. “When a dry coffee pack is hit by high pressure with water, it collides with almost 100 meters above the atmospheric pressure, 100 meters above the sea level, but it expands compactly.
The team is currently considering the results in numerical and theoretical models of porous bed extraction. They also edit atlas of different types of espresso packs based on coffee micro-CT imaging.
“What we find will help the coffee industry brew more knowledge,” MyCK said. “Many people follow procedures based on unconfirmed intuitions or claims that have not been proven to be confirmed. Furthermore, there is truly interesting data on the pressure-induced flow of coffee. The results were also surprising to us.
