Cracking the Code: Scientists Unveil the Key to an Exceptional Cup of Coffee
Unlocking the secret to a perfect cup of coffee: Recent scientific research delves into the age-old theory that adding water at the right time could significantly enhance the flavor and quality of your brew
Coffee enthusiasts have believed for a long time that adding a small amount of water to coffee beans before grinding them could have a significant impact. A recent study conducted by University of Oregon researchers appears to validate this theory. The study investigated the impact of this technique, originally intended to streamline the coffee-making process, on the flavor profile of the brew.
"According to study coauthor Christopher Hendon, an associate professor of computational materials chemistry at the University of Oregon, when you grind coffee, it goes everywhere. Dust comes out of the grinder, creating a plume that covers everything. However, if you add a little water, it seems to not go everywhere and is cleaner. This was the primary reason people did it."
Espresso cup, coffee beans, ground coffee, coffee capsule and instant coffee
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A recent study suggests that coffee, particularly ground and caffeinated varieties, can decrease the risk of heart issues and premature death. This is due to the static electricity generated by friction during the bean grinding process, causing the particles of ground coffee to repel each other and scatter in various directions.
Water serves as an insulator, dampening this process known as the "Ross droplet" technique, which was initially proposed on a home barista forum. The concept, borrowed from the materials production industry, was intended to minimize mess, but has since evolved into a more refined method for achieving a superior brew. The theory behind this evolution is that by reducing static electricity, water not only prevents ground coffee from dispersing or sticking to the grinder, but also inhibits the formation of microscopic clumps during brewing.
Clumps are problematic because they cause water to flow around them, leaving coffee untouched and flavor behind. In barista terms, they reduce extraction yield, meaning less coffee ends up dissolved in the cup. According to Hendon, clumps result in void space similar to stacked watermelons, leading to lower surface area contact with water and therefore decreased extraction.
The study, released on December 6 in the journal Matter, examined this less obvious, more challenging to detect potential advantage of including water to the beans: eliminating flavor-robbing microclumps.
Start with a single drop of water and build up from there, experts say.
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Testing Ross Droplet Performance
Two volcanologists were part of the research team, and they repurposed a tool typically used for measuring electric charges on wildfire and volcanic ash. They meticulously weighed the coffee before adding water using a precise pipette that measured in micrograms. The coffee was then ground in a professional grinder, one of the fastest on the market and a popular choice in cafes.
Hendon mentioned that the addition of small amounts of water, ranging from one droplet upwards, passivates the static charge, ensuring that the coffee exits the grinder without having been charged. He admitted that it's unclear exactly what the water is doing, but suggested that it may be absorbing the charge or altering the temperature inside the grinder to lessen the effects of friction.
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By adding enough water, you can prevent clumping and increase extraction efficiency, resulting in less waste. This creates a larger surface area for the water to work with.
When the brewing water comes into contact with the ground beans without clumps, it reduces wasted coffee and results in a more consistent brew. The amount of water needed can vary depending on factors such as roast type and grind coarseness, so there is no one-size-fits-all rule. On average, adding water increases extraction yield by 10%, according to the study. However, this may not always translate to a noticeable difference in flavor, but it does reaffirm the benefits of the "Ross droplet" technique, as warned by Hendon.
Ever since the study was published, I've been inundated with emails from people expressing their gratitude, stating that from a cleanliness perspective, this is a significantly huge improvement," Hendon noted. "For the average homeowner, I would suggest starting with just a single drop of water and gradually increasing from there as there is a considerable level of complexity involved in this process."
However, there is a catch: The water enhances cleanliness regardless of the brewing method, but the brewing advantage is only evident in espresso and, to a lesser extent, filter coffee. When using a cafetiere, French press, or AeroPress, not much changes because, due to the coarser grind required for these methods, "all of the water is already in contact with all of the coffee," explained Hendon.
Lance Hendrix, a coffee connoisseur and experienced barista unaffiliated with the study, has attempted to recreate the findings and shared his results in a detailed YouTube video. He commended the study for its efforts to clarify the process of water spritzing on coffee beans, but suggested that further testing with various grinder models is needed for more conclusive evidence.
However, based on his own tests, he said he thinks the benefits are plausible.
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"The amount of water needed for the alleged benefits varied greatly from one grinder to another," he stated. "Although I don't believe there is a one-size-fits-all solution from this study to immediately improve coffee brewing at home, I do think it is a valuable contribution to the ongoing efforts to understand the highly complex process of grinding, which is arguably the most crucial aspect of brewing a cup."
François Knopes, a professional coffee roaster and taster at the Independent Coffee Lab, who was not involved in the study, shared that he regularly sprays his beans before grinding for tasting purposes and would recommend this for anyone brewing coffee at home. However, he believes that this might not be practical in other settings.
Knopes stated that for most professional setups, like a coffee shop serving large quantities of espresso-based drinks daily, the process would be extremely time-consuming. He suggested that professional baristas should consider seeking improved grinding technologies or de-clumping devices to enhance extraction, such as little needles to break up the grounds and remove any boulders generated during grinding.
Hendon concurred, noting that at present, adding the additional step of pre-infusion may be impractical. However, he anticipated that future technologies would be developed to support the concept, recognizing the potential power of adding water on demand.
