Electric Current Could Brew a Better Cup of Coffee
▼ Summary
– University of Oregon chemist Christopher Hendon discovered a novel method to measure coffee’s flavor profile by sending an electrical current through a sample.
– In 2020, Hendon’s lab developed a mathematical model for brewing espresso that relies on extraction yield (EY), the fraction of coffee that dissolves into the beverage.
– The model for extraction yield is based on how lithium ions propagate through battery electrodes, similar to how caffeine dissolves from coffee grounds.
– In 2023, Hendon’s team found that static electricity, or triboelectricity, from grinding beans causes microscopic clumps, particularly at fine grind levels.
– Adding a squirt of water to beans before grinding reduces static charge and clumping, lessening waste and producing a consistent espresso flow.
For University of Oregon chemist Christopher Hendon, coffee isn’t just a morning ritual,it’s a serious scientific pursuit. His latest breakthrough involves a clever new method to assess a coffee’s flavor profile by running an electric current through a brewed sample. The findings were recently published in Nature Communications.
We’ve tracked Hendon’s coffee research for years. Back in 2020, his lab developed a mathematical model for brewing consistent espresso shots while cutting down on waste. That challenge stems from the sheer complexity of espresso: roughly 2,000 different compounds are extracted from coffee grounds during brewing. Reproducing a perfect cup reliably is no small feat for baristas.
To solve this, Hendon and his team created a model based on extraction yield (EY),the fraction of coffee that dissolves into the final drink. Controlling water flow and pressure as liquid passes through the grounds is key. Interestingly, the model borrows from battery science, specifically how lithium ions move through electrodes, mirroring how caffeine molecules dissolve from coffee.
Three years later, Hendon’s group shifted focus to why microscopic clumps form, especially with very fine grinds. The culprit? Static electricity generated by fracturing and friction during grinding. The technical name is triboelectricity, where opposite charges build up when two materials rub together.
This same charge buildup happens during volcanic eruptions. So Hendon teamed up with volcanologists Josef Dufek and Joshua Méndez Harper, who frequented the same local coffee shop and noticed striking parallels between coffee science and volcanic ash, magma, and water.
Their experiments confirmed a simple fix: adding a single squirt of water to coffee beans before grinding dramatically reduces static charge on the grounds. This minimizes clumping during brewing, cuts waste, and ensures the strong, consistent flow needed for a tasty espresso. Skilled baristas already use this trick, known as the Ross droplet technique. But Hendon’s team was the first to rigorously test it and measure the actual electrical charge on different coffee types.
(Source: Ars Technica)