Why Fluid Bed Roasting?
In November 1974 Michael Sivetz applied for a patent for a fluid bed coffee roasting machine (the same roasting method employed by The Power Roaster). In his patent application, Mr Sivetz included this description of current, then and now, commercial coffee roasters:
Accepted commercial coffee bean roasting methods have not undergone any significant recent improvements in efficiency or simplification. The principles employed in widely utilized coffee roasters are virtually the same as used over 50 years ago. One exception is that about 40 years ago a continuous rotary cylinder roasting machine was developed by the Jabez Burns & Sons, Inc. Company in the United States. The commonly utilized prior art roasters employed rotating steel cylindrical roast chambers which held the coffee bean charge occupying only about 15 percent of roast chamber volume, and which cylinder was rotated about a horizontal axis at rates of typically 60 to 90 revolutions per minute. Hot recirculatory gases are passed about and through the cylinder, but not necessarily through the beans therein, at temperatures from 650.degree. to 700.degree.F., or even higher. Coffee roasting times varied from 10 to 30 minutes, and uniform roasting of each bean was not routinely achieved.
In addition, Mr. Sivetz cites the heat source of these machines as being propane gas. Recently there has been discussion that the use of propane gas can possibly contaminate the roasted coffee with carcinogens. The vast majority of large commercial roasting operations use propane gas as their heat source. Fluid Bed Roasting uses electricity only as its heat source eliminating the creation of carcinogens. It is a much cleaner process!