Researchers at the University of Warsaw have uncovered insights into channeling during espresso brewing, which significantly affects extraction yield and quality. This finding aims to help coffee lovers achieve more consistent results.
The brewing process involves water flowing through a bed of finely ground coffee, but “channeling” occurs when the water branches off in different paths, reducing extraction yield and quality. A study published at the American Physical Society’s Global Physics Summit revealed that optimizing water flow and pressure can improve the final brew.
Industry standards set by the Specialty Coffee Association dictate specific guidelines for espresso brewing, including temperature, pressure, and coffee-to-water ratios. However, many coffee shops deviate from these rules due to flexibility in brewing machines.
Scientists like Christopher Hendon have made significant progress in understanding the science behind perfect espresso brewing. His lab developed a mathematical model that focuses on controlling water flow and pressure to minimize waste and achieve optimal extraction yield.
The key to consistent espresso lies in using fewer coffee beans, opting for coarser grinds with less water, rather than adjusting brew time. By applying this approach, baristas can create more reproducible results and elevate their brewing skills.
Source: https://arstechnica.com/science/2025/03/the-physics-of-brewing-the-perfect-espresso