If you’re a home barista, chances are you’ve stumbled upon a peculiar advice: spray your coffee beans with water before grinding. This trick, known as the Ross Droplet Technique (RDT) ¹, is not just a fad.
It’s a method steeped in science to reduce the static mess created during grinding. But a recent scientific paper reveals there’s more to this technique than meets the eye.
Why Add Water to Coffee Beans?
The primary reason for spritzing coffee beans is to combat static electricity. When you grind coffee, you generate static in two main ways: triboelectrification and fractoelectrification.
The friction and breaking of beans during grinding create interfacial heat, leading to static buildup. This static causes the finely ground coffee particles to stick to everything but where you want them.
The Unexpected Impact on Coffee Brewing
The new study ² delves into the effects of water on coffee grinding. It turns out that adding water does more than just reduce static; it significantly alters the brewing process.
The research shows that when beans are spritzed with water, there’s a notable decrease in flow rate and an increase in extraction during espresso brewing. This finding contradicts the common experience of many baristas, who haven’t observed such changes in their brewing routines.
The Science of Electroclumps
One of the paper’s intriguing concepts is the formation of “electroclumps.” These are aggregates of coffee particles with varying charges that clump together due to static.
When added, water prevents the formation of these electroclumps, leading to a more even distribution of fines in the coffee puck—this results in slower flow rates, higher contact times, and potentially higher extractions with less channeling.
The Grinder Experiment
The study’s findings raise questions about the impact of this technique across different grinders. Experiments with various grinders, like the DF64 and Eureka Mignon Oro, showed inconsistent results regarding brew time changes when water was added.
This inconsistency suggests that factors like grinder material and design significantly affect how water affects the grinding process.
To further explore these findings, there’s a call for coffee enthusiasts to participate in an experiment. By comparing brew times with and without spritzed beans across different grinders, we can collectively deepen our understanding of this phenomenon.
Unanswered Questions & Future Explorations
Despite the intriguing results, many questions remain. Does this technique impact filter coffee brewing? Is the taste profile of coffee brewed from water-spritzed beans preferable to dry beans?
These are areas ripe for exploration, and the coffee community is encouraged to share their findings.
A New Frontier In Coffee Science
This study opens a new frontier in coffee science, highlighting the complex interplay between grinding, static electricity, and brewing. It’s a call to experiment, to question, and to share findings.
Whether you’re a seasoned barista or a curious coffee lover (be sure to check out this article on how to make the best coffee at home), this research invites you to explore the fascinating world of coffee science.
Martha A. Lavallie
Martha is a journalist with close to a decade of experience in uncovering and reporting on the most compelling stories of our time. Passionate about staying ahead of the curve, she specializes in shedding light on trending topics and captivating global narratives. Her insightful articles have garnered acclaim, making her a trusted voice in today's dynamic media landscape.