To prepare an exceptional cup of coffee, two essential prerequisites are required: that the finest quality of green coffee beans are used, and that these are fresh roasted. Roasted coffee is an extremely perishable product. It is almost as sensitive as the most perishable produce found in the market. Within two weeks from the roast date, 50-60% of the flavor is lost. However, sophisticated packaging technology can reasonably extend the shelf life to several months. Once a package is opened, however, the clock starts ticking on the shelf life of coffee.

Roasting
Roasting is the last and most important step in a long sequence of processing that the beans go through after they are harvested. Coffee does not grow ready to use. All coffee must be roasted before it can be ground and brewed.

Unroasted coffee is referred to as "green coffee." In contrast to roasted coffee, green coffee has a shelf life of about a year. Green coffee beans are small, dense and very hard. They may be unrecognizable to those outside the coffee trade. Green coffee has a grass-like smell. It bears little resemblance in appearance or flavor to what we commonly think of as coffee beans. It is the process of roasting which produces the characteristic flavor and wonderful aroma we know as coffee.

The Roasting Process
Generally speaking, the process of coffee roasting is a time-temperature dependent process whereby physical and chemical changes are induced in the green coffee. The average temperatures range from 375 degrees to 450 degrees for a period of 8 to 20 minutes depending on the volume of beans in the roaster. When the green beans are loaded into the roaster they drop into the roasting chamber, a rotating cylinder filled with internal paddles that keep the coffee tumbling over itself. Convective hot air and radiant heat are the most common heat sources.

In the first stages of the roast the green beans gradually yellow. The temperature is raised to the boiling point of water, driving off the moisture in the beans. As the moisture trapped in the bean turns to steam, it bursts the cellular structure of the bean so abruptly that the bean swells with an audible crack or popping sound. This loss of moisture as well as other volatile compounds reduces the weight of the bean by 14-23%, and increases its size by 40- 60%. This near doubling of the size of the bean decreases its density.

In the second stage of the roast, after the removal of moisture, proper roasting begins. As the temperature of the bean escalates, a complex series of chemical transformations occurs. This process is called pyrolysis. "Pyro" is Greek for fire or heat. Pyrolysis, then, is the metamorphosis by heat of the chemical components in the bean.

There are literally hundreds of chemical compounds that make up the composition of green coffee. Among these are oils, complex polysaccharides, sugars, starches, fats, waxes, and others. Some of these are broken down by the heat and driven off. Many compounds extracted during brewing are not present in green coffee at all. Rather, they develop as the coffee is roasted. Some are starches which are converted into sugar. The sugar, when caramelized, accounts in part for the brown color of the coffee.

As roasting progresses, additional complex proteins and organic acids are broken down and transformed. The bean develops further in size, and becomes a darker brown. To produce the darker roasts, the beans are left in the roaster longer. As the temperature continues to build, the aromatic oils volarilize and boil toward the surface, causing a second crack or popping.

Finally the roastmaster determines that the roast is done. The beans are emptied from the roasting drum into the cooling bin. In the cooling bin the beans are cooled down rapidly to stop further development and loss of aromatics.

The Roastmaster
It is said that coffee roasting is an art form. The skilled roastmaster must know his coffees intimately and take into consideration the natural properties possessed by each type of coffee. Each coffee variety has its own unique flavor characteristics depending on the elements of the environment that created it. The performance of the roastmaster is physically demanding. It requires enormous patience, and that the senses be acutely tuned. The roastmaster must hear how the roast pops, smell the developing aromas, and identify the right shades of color. He draws upon experience and knowledge to properly adjust airflow, time and temperature while the roast is in progress.



It is important not to roast too quickly. A bean scorched or charred on the outside may yet be unroasted on the inside. It is equally important not to roast too slowly at low temperatures, since this bakes the bean, leaving it underdeveloped and with a flat flavor. While the beans are tumbling in the roasting drum, he inserts a sample puller to draw off small samples for closer inspection. He makes the final judgment on the basis of bean development and surface color.

Good timing is important throughout the roast but it becomes critical when a roast is at its peak. It is a split second decision when the roast is done. A second too soon and the roast could fall short of perfection. A second too late, and the roast could be lost.

The roastmaster is not just a machine operator. He must skillfully manipulate the roaster as a tool to bring each coffee to the precise point where it offers optimal flavor potential.

Freshness
Freshness is probably the most misunderstood factor about coffee. The date of the roast is the key to freshness. Without sophisticated packaging, coffee beans lose more than half of their flavor within two weeks. After six weeks the oils become rancid. Exposure to air and moisture accelerates the decomposition of the flavors. Freezing the beans may stop this decomposition but freezing also destroys the delicate oils and aromatics. Never freeze a quality fresh roasted