Scientists brew up a mathematical formula for the ideal coffee
Could a more consistent and enjoyable cup of coffee also be a lot better for the environment? A team of scientists have created a mathematical model for what they say is the ideal brew, recommending that a less-is-more approach could lead baristas to produce one heavenly espresso after another, using around a quarter fewer beans.
The research team was made up of chemists, mathematicians, material scientists and coffee enthusiasts from five countries. Together, the researchers analyzed the standard 20-gram (0.70-oz) portion of coffee grounds typically used by espresso makers around the world to see if there was a way this process could be optimized.
This meant looking at grind size, the water pressure created by the espresso machine as it pumps the water through, the flow rate, and the amount of grounds going into each brew. Leaning on electrochemistry to observe how caffeine and other molecules dissolve out of the grounds, the team then built a mathematical model that enabled them to predict and test the metrics of different brewing methods.
Through its analysis, the team calculated the extraction yields of the different brewing methods, which refers to the percentage of solid coffee grounds that end up in the cup as a liquid. Counterintuitively , the team found that using less coffee actually led to higher yields, and did so on a more consistent basis, with less variation in flavor profile.
“The real impact of this paper is that the most reproducible thing you can do is use less coffee,” says University of Oregon chemist Christopher Hendon. “If you use 15 grams (0.53 oz) instead of 20 grams of coffee and grind your beans coarser, you end up with a shot that runs really fast but tastes great. Instead of taking 25 seconds, it could run in seven to 14 seconds. But you end up extracting more positive flavors from the beans, so the strength of the cup is not dramatically reduced. Bitter, off-tasting flavors never have a chance to make their way into the cup.”
Of course, the idea of a perfect tasting coffee is going to be a matter of subjectivity. What is not a matter of subjectivity, however, is that less waste is a good thing. On that, the scientists say this 25 percent reduction in coffee grounds could save American cafes as much as US$1.1 billion a year, in addition to the huge environmental benefits.
“We want to extract more from the coffee to save money, and be sustainable, but we also want it to taste delicious, not burnt or bitter,” says Hendon. “Our method allows us to accomplish that.”
The research was published in the journal Matter.