Coffee bean acoustics

May 22, 2014
Coffee beans roasted into second crack. Credit: Preston S. Wilson

People around the world are drawn to coffee's powerful allure—for its beloved smell, and taste, and for the caffeine boost it provides. As you enjoy your coffee beverage, however, odds are good you're probably not thinking about the coffee bean roasting process behind it.

But for some the love of runs so deep that they go so far as to roast their own . Controlling the roast time and temperature profile allows them to dial in the range of roast levels from light to dark, which greatly affects the style, flavor, and aroma of the resulting beverage.

This drove Preston S. Wilson, a coffee aficionado and acoustician who normally focuses on studying underwater acoustics in his role as an associate professor in The University of Texas at Austin's Cockrell School of Engineering, to explore the potential of using the "cracking" sounds emitted by coffee beans during the roasting process—as the basis for an automated acoustical roast monitoring technique.

These coffee roasting sounds are well known within the coffee roasting realm, but this is believed to be the first quantitative assessment of these sounds and the first suggestion to use them in an automated control process.

As Wilson reports in the Journal of the Acoustical Society of America—Express Letters, he found three parameters of the crack sound that could be exploited. Near the end of the roasting process, sounds known as "first crack" exhibit higher acoustic amplitudes than the "second crack" sounds that are emitted later. Finally, the rate of cracks in the second crack chorus is higher than the rate in the first crack chorus.

"The sound of the first crack is similar to popcorn popping, while the second crack is more akin to the sound of the breakfast cereal Rice Krispies," explains Wilson.

Initially, Wilson's unfunded project was just to "satisfy his own interest as a person who roasts coffee," but a commercial application may emerge for the coffee roasting industry.

An automated acoustical roast monitoring technique "could lead to optimized coffee roasting, which would increase quality, decrease errors in roasting, and potentially save energy used to power the roasting process," he says.

Taking it to the next level and commercializing the process will "require quite a bit of effort—engineering the design of the sensor system, the data acquisition and processing," Wilson adds. "It will require writing software to automatically process the sounds, and then integrating it into the control system."

Explore further: Green coffee benefits prove limited in mice research

More information: The article "Coffee roasting acoustics" by Preston S. Wilson appears in the Journal of the Acoustical Society of America—Express Letters. See: dx.doi.org/10.1121/1.4874355

add to favorites email to friend print save as pdf

Related Stories

Torrefacto-roasted coffee has higher antioxidant properties

Mar 06, 2008

Torrefacto-roasted coffee has higher antioxidant properties than natural roast, according to the dissertation defended by a biologist of the University of Navarra, Isabel López Galilea. She has emphasized in her study that ...

Pistachios make healthy decafs

Jun 23, 2011

If caffeine gets your blood pumping more than it should, here's a piece of good news: when roasted appropriately, pistachios can become a tasty and healthier substitute for coffee, with all the aromas and ...

Green coffee benefits prove limited in mice research

May 01, 2014

The efficacy of green coffee extract to impact on an independent risk factor for cardiovascular heart disease has been proven ineffective in mice models fed high fat diets (HFD) a recent study has shown.

Recommended for you

Finding faster-than-light particles by weighing them

Dec 26, 2014

In a new paper accepted by the journal Astroparticle Physics, Robert Ehrlich, a recently retired physicist from George Mason University, claims that the neutrino is very likely a tachyon or faster-than-light par ...

Controlling core switching in Pac-man disks

Dec 24, 2014

Magnetic vortices in thin films can encode information in the perpendicular magnetization pointing up or down relative to the vortex core. These binary states could be useful for non-volatile data storage ...

Atoms queue up for quantum computer networks

Dec 24, 2014

In order to develop future quantum computer networks, it is necessary to hold a known number of atoms and read them without them disappearing. To do this, researchers from the Niels Bohr Institute have developed ...

New video supports radiation dosimetry audits

Dec 23, 2014

The National Physical Laboratory (NPL), working with the National Radiotherapy Trials Quality Assurance Group, has produced a video guide to support physicists participating in radiation dosimetry audits.

Acoustic tweezers manipulate cell-to-cell contact

Dec 22, 2014

Sound waves can precisely position groups of cells for study without the danger of changing or damaging the cells, according to a team of Penn State researchers who are using surface acoustic waves to manipulate ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

swag
not rated yet May 22, 2014
Good grief. It's insane what passes for research that gets funded these days.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.