How Scott Rao is raising the rate of extraction through experiments with the DE1 espresso machine.
BY CRAIG BATORY
SPECIAL TO BARISTA MAGAZINE ONLINE
Photos courtesy of Scott Rao
Coffee professional Scott Rao has been known to dive deep into several aspects of specialty coffee; one in particular is espresso extraction. Since 2016, Scott has shared several data points on his blog and Instagram showing the possibilities of producing great-tasting espresso with shots that last over 60 seconds, containing 25% or more coffee solubles with a brew ratio of 1:3 and 1:4. To produce these results, Scott worked with Decent Espresso founder John Buckman, using a DE1 espresso machine.
The current standards for espresso across the United States can arguably be defined by 30-second shots using a 1:2 coffee-to-water ratio. One reason for this standard can be traced back to Andrea Illy’s book, Espresso Coffee: The Science of Quality written in 1995. In the book, Andrea suggests that espresso extraction should be around 30 seconds with a 1:2 ratio. He opined that anything less is probably sour and under-extracted, while anything more is most likely over-extracted, astringent, and burnt. Scott, however, is seeking to prove that higher extraction doesn’t always produce astringent tastes, and that longer shot times don’t always burn the espresso. Under the right circumstances, a shot can last much longer than 30 seconds and have a much higher—or lower—coffee-to-water ratio, and still taste great.
As seen from Scott’s experiments, the highly extracted profiles can be described as a long pre-infusion with a gentle ramp in pressure to climax, followed by a slow falloff in pressure until the 1:3 or 1:4 ratio is achieved. The pre-infusion lasts upwards of 13 seconds, followed by 30 to 40 seconds of descending pressure water flow. The overall shot duration lasts 60 seconds or longer. The result: a shot with 25% (or more) coffee solubles that produce the best taste for nearly any type of coffee. “On average, the shot does taste better,” said Scott about his high extraction profiles. “Several people came to my booth at the World of Coffee in Europe and tasted super high extractions with their own coffee and tasted flavors they had never tasted before. The feedback was overwhelmingly positive.”
The DE1 espresso machine Scott uses is operated exclusively from an Android tablet and provides a live feed of the espresso extraction. It allows the user to change the pressure profile, flow rate, and water temperature in real time during the extraction. However, Scott stressed that a barista doesn’t need a super sophisticated espresso machine to achieve similar results to his. “The profile would be hard to achieve on other machines,” said Rao. “But that doesn’t mean it’s not doable. A well-balanced [highly extracted] espresso shot is not all based on the quality of the espresso machine.” He explained that a great, highly extracted shot has more to do with the espresso preparation and the barista’s knowledge of the coffee and the machine—and how they can use the machine to produce the results they want. “A barista can start at a 1:2 ratio and still pull a great-tasting espresso shot with high extraction, all things being equal,” said Scott.
He went on to explain that while all variables are important to extracting espresso, a few rank higher than others. “A good, highly extracted espresso can be defined by puck prep and good particle distribution,” Scott added, meaning the grounds in the portafilter are evenly distributed and allow for consistent water flow. “Grind distribution is one major thing that separates a good shot from a bad shot. Not necessarily particle set distribution of the grinds, but how the grounds are distributed in the puck. From that perspective, you get good flow rate, you get a better-tasting espresso, and you can get higher extraction with the right profile,” Scott said. This means using a grind distribution tool to spread the grounds in the portafilter, as well as having a grinder that produces consistent grounds each shot.
Along with redefining espresso extraction in the specialty-coffee industry, Scott’s approach to high extraction could lead to more sustainable business practices in specialty coffee. For example, higher extraction means cafés could use less coffee and get better-tasting coffee. “If you’re a roaster that has a café, this means over time you could brew less coffee in the café and spend more money on better-quality green coffee,” said Scott. It could also mean café owners could spend more money on staff training and better brewing equipment.
Scott’s experiments with Decent’s profiling software are potentially influencing espresso machine manufacturers, cafés, and baristas to adopt their own flow profiles and extraction methods to improve on the norms set by industry leaders such as Andrea Illy. Coffee is inherently subjective. It has so many variables and is constantly changing, so as coffee professionals, we must strive to continue to push the bar on what defines a “great tasting espresso.”
“Data and feedback are crucial to becoming a better coffee professional,” said Scott. “Just because you pull three shots in a row that are all 30 seconds doesn’t necessarily mean it’s the same shot. We can look at the data and use it as feedback to make us better.” Scott’s research and tests can be seen on his Instagram and on his blog dating back to 2016.
ABOUT THE AUTHOR
Craig Batory is a coffee professional, journalist, and digital marketer currently based in Detroit. You can reach him directly at hello@craigbatory.com.
