It’s unlikely that you’ve poured over coffee bean acoustics as you sip a latte, but for Preston S. Wilson, underwater acoustics associate professor at The University of Texas, exploring the sounds emitted by coffee beans roasting was a matter of sound engineering, great curiosity, and the eventual discovery of an increasingly sustainable solution for the procedure resulting in a perfected morning brew.

During the roasting process, the physical properties of green coffee beans are baked into a perfected consumable with a distinct flavor, smell, and density. As the green beans roast, they make crackling and popping noises.  The sounds may have little differentiation or pattern to the untrained ear, but Wilson, in his quantitative assessment and measurement of these sounds, found three parameters of the sounds the beans were making. At “first crack,” higher acoustic amplitudes were recorded. Later in the roasting process, a “second crack” was detected. As the roasting continued, the rate of the noises played out in a chorus higher than the first crack chorus.

Wilson reported his full assessment of coffee bean acoustics in the Journal of the Acoustical Society of America – Express Letters. His detailed measurements revealing the acoustical pattern in coffee roasting held the potential of perfecting an automated roasting technique, with the use of acoustical monitoring.

Wilson explained that his discovery, “could lead to optimized coffee roasting, which would increase quality, decrease errors in roasting, and potentially save energy used to power the roasting process.”

This sustainable process might have put a little more “green” into the green bean roasting process, thanks to acoustical precision.

If you have questions about sound testing and measurement, or would just like to talk with an expert in the field, contact our team at CENSEO AV+Acoustics. We enjoy talking solutions.

Source: Coffee Roasting Acoustics by Preston S. Wilson, Journal of the Acoustical Society of America – Express Letters
Photo Credit: Home Barista


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