The following article was written in 2002 by the late Michael Sivetz, inventor of the fluid bed coffee roaster. The opinions expressed in this article are not those of coffeechemistry.com, as such we don't endorse nor deny any of its claims. This article is only meant for educational purposes.
Unlike products other food products which require minimal amounts of thermal processing, coffee undergoes a dramatic chemical changes before it even exhibits any hint of its aromatic complexity. For this to occur, we must pass the coffee over the fire, so to speak, and transform this relatively boring bean into a bean with a myriad of complexity.
The transformation from raw bean to finished product is perhaps one of the more complex stages in coffee production.
If you take a lot of green beans and smell it, it hardly has any of the characteristics that we would typically associate with roasted coffee. Yet once roasted, the raw materials within the raw bean undergo a significant transformation to give rise to hundreds of new compounds that we can appreciate.
Unlike wine where the winemaker has complete control of the product up to the time of bottling, coffee requires that the consumers use a bit of their own skills during beverage preparation. This final step in coffee preparation is perhaps one of the most critical, since errors here can ruin the quality of the coffee and ultimately all the work that was invested into it.
Before we can fully appreciate a finely brewed cup of coffee, we must take the laborious task of extracting important flavoring materials locked within the bean. The easiest way to do this of course, would be to place the entire set of beans in hot water and agitate - eventually after much time the flavoring material would extract into solution, but this method would soon prove impractical.
Cupping is perhaps one of the most important skill anyone can develop within the coffee industry. Initially developed by green coffee buyer, "cupping" provides a consistent methodology for evaluating a coffee's quality before determining a price on a lot. In much the same way that a wine connoisseur would evaluate a fine Cabernet, cuppers must use a strict set of tasting protocols to assess quality.