UC Davis Coffee Center Contributes Research to New Brewing Control Chart
Since its development in 1957, coffee professionals and home brewers have turned to the Coffee Brewing Control Chart for a defined standard of coffee brewing. Coffee science has come a long way since the ’50s, however, and so a team of researchers at the new University of California, Davis, Coffee Center — supported by the Specialty Coffee Association and the Coffee Science Foundation and with funding from Breville — sought to update the resource for the 21st century. The result is the Sensory and Consumer Brewing Control Chart, which combines new coffee science with consumer research and a more user-friendly approach.
Building upon the work of Ernest E. Lockhart, the biochemist and first director of the Coffee Brewing Institute responsible for the original chart, researchers from UC Davis began working on the new chart in 2017, setting out to gain as much sensory data as possible to inform the new chart. The process was straightforward but labor-intensive, says William Ristenpart, a professor of chemical engineering at UC Davis and founding director of the Coffee Center.
To gather data, the researchers conducted tasting panels of small teams (12 volunteers each) and consumer preference tasting, brewing coffee in different styles for mostly UC Davis college students. The consumer preference data was combined with the researchers’ technical and sensory data and condensed to create the new chart.
The new chart is a more streamlined version of the previous chart, showing different flavor profiles based on the total dissolved solids (amount of soluble material extracted from the coffee) and extraction yield (percentage of coffee grounds that dissolve during brewing). Ristenpart says that using a scale and comparing your coffee-to-water ratio to the graph while adjusting grind size and brew time will give you a good idea of what sort of flavors you can expect.
Ristenpart notes that using the chart, it is even possible to accentuate certain flavors and make a single coffee taste markedly different, depending on how it is brewed.
“You could take the same pile of coffee beans and then, depending on how you grind them and how you extract them, get them to different corners of the Coffee Brewing Control Chart, which will make those same coffee beans taste differently.”