"The roasting of green coffee beans develops the coffee aromas and flavors. Roasting is the process of heating the coffee beans uniformly, first to remove the moisture (about 12%) then to cause pyrolysis of the sugar in the bean cells, which means that the sugars break down to caramel, water, carbon dioxide, and many aldehydes and ketones which characterize the aroma and taste of fresh coffee.

The roast weight loss is related to bean color and beverage taste, and is often related to the mode of brew preparation and cultural taste. Different coffee beans react differently to the various end temperatures cited. And various green beans have preferred levels of roast for best flavor developments. In the USA, too many firms roast their beans too lightly, because that gives less weight loss (greater yield and profit). Often roast level is determined by the coffee buyer-taster who is used to evaluating green coffee beans at light roasts. The end result of such light roasts can be a very acid, astringent, harsh-tasting beverage which does not have optimum flavor development. It is a wasted coffee sold to the public.

Few people realize that the manner of roasting has a great deal of influence on the taste of the final roasted beans. For example, rotary steel cylinder roasters, which are traditional in the trade; e.g., Probat in Europe, due to their high operating temperatures (over 800o F) cause scorching of the beans, oil release that can coat all the beans, and smoke from burning chaff that fumigates the beans, giving them a harsh, biting, and (in dark roast) a burnt taste which is "dirty." The use of Melitta filter paper, for example, helps remove some of this bitey taste. It is far better not to scorch or burn the beans or lay a tar coat on the bean. In order to avoid this scorching and non-uniform roasting of coffee beans, Mike Sivetz developed, in 1975, a fluid bed "once-thru-air" coffee bean roasting machine that produces a clean "tar-free" non-biting, smooth tasting beverage.

Further, the Sivetz fluid bed roaster, with thermal bean sensor, is the only roaster that can measure true bean temperature, because the probe is in a stationary box containing the fluid bed of beans. This accuracy cannot be directly achieved by rotary cylinder machines due to the pure mechanical difficulty of probing a moving mass. You are truly receiving the best possible product available in the market today."*

The Sivetz hot-air roaster allows each bean to develop its naturally distinctive flavor without the smoke and tar contamination that occurs in many roasters. You will gain confidence as your customers try new coffees and note the subtle differences, especially when they keep returning to you for more!