Air roasted coffee is a noteworthy product that is different than many commerical roasters, who commonly utilize drum roasters to prepare their coffee beans. This roasting method was championed by Michael Sivetz, Chemical Engineer and Coffee Industry Consultant. He wrote the first scientific discourse on coffee called, Coffee Technology, and developed and manufactured the first practical commercial air roaster: the Sivetz Fluid-Bed Roaster.
Most drum roasters today introduce hot air into their roast chamber where the beans tumble and touch the hot surfaces to roast, like clothing in a clothes dryer. The Sivetz system levitates the beans on a fluidized bed of hot air, keeping the beans moving- not scorching on hot surfaces. The exclusive use of hot air greatly increases the rate of heat transference to the beans, creating a cleaner, more aromatic roast and decreasing bitter notes. Sivetz sold hundreds of these roasters all around the world, and many have been inspired to create their own air roaster based on his unique design.