Depending on the day, coffee is either the number one or two most consumed beverage in the world. It is enjoyed daily by hundreds of millions of people in virtually every country around the globe.
Many fresh roasted coffee lovers have no idea how their favorite morning cup of coffee is ‘made’. This article briefly explains the process of roasting gourmet coffee beans and how those wonderful flavors and aromas’ get into your morning cup!
It takes around fifteen to twenty minutes to roast gourmet coffee beans using a typical small commercial gas roaster. The usual rule-of-thumb is the quicker the roast, the better the coffee.
Short roasting retains the largest percentage of the gourmet coffee bean’s aromatic properties. Slow roasting gourmet coffee beans results in the beans baking and usually prevents them from developing fully. Also slow roasting normally won’t produce bright roasts and typically makes the beans hard instead of brittle even after the color standard has been attained.
Gourmet coffee beans have varying degrees of moisture when they are green or raw. The best fresh roasted coffee is created by first starting the roasting process with a slow fire until some of the moisture has been driven out of the bean. If too much heat is used at the beginning of the roasting process there is a high risk of “tipping” or charring the little germ at the end of the bean which is the most sensitive part of the bean.
“Kissing The Cheeks” of a gourmet coffee bean is caused by loading too many beans in the roasting cylinder at one time and revolving the roasting cylinder too fast. This causes some of the beans to ride the cylinder walls for a complete revolution instead of falling off the sides into the cylinder as it revolves. As a result one face of the gourmet coffee bean gets burned or ‘kissed’.
There are no universal standards for coffee roasting. Because roasting is part ‘art’, a roaster will develop a personal blend and roast combination and establish that blend/roast combination as a sample ‘type’ to be used as the in-house standard the next time a batch of that blend/roast is roasted. Coffee drinker’s tastes run the entire gambit of roasting possibilities, from light roasted to extremely dark roasts.
Many roasters use the following roasting classifications:
- Full City
A city roast is a dark roasted bean. A full city roast is a few degrees darker yet. A French roasted bean is cooked until the natural oil appears on the surface. And an Italian roasted bean is roasted until it is carbonized so it can be easily powdered.
In the United States, lighter roasted beans are favored on the west coast, the darkest roasts are enjoyed in the south and a medium-colored roast is the primary roast enjoyed on the east coast. Coffee drinkers in Boston especially enjoy cinnamon roasted coffee.
Coffee loses weight during the roasting process. The amount of weight lost varies according to the degree of roasting and the nature of the bean. Green beans, on average, loose sixteen (16%) percent of their weight during the roasting process. Typically one hundred pounds of coffee in the cherry produces twenty-five pounds in the parchment. One hundred pounds in parchment produces eighty-four pounds of cleaned coffee. And one hundred pounds of cleaned coffee produces eighty-four pounds of fresh roasted coffee.
During the roasting process the gourmet coffee bean undergoes both physical and chemical changes. After it has been in the roasting cylinder a short time the color of the bean turns a yellowish brown which gradually darkens the longer it is cooked. Likewise as the beans heat up they shrivel up until they reach the halfway point of the roasting process called the “developing” point. At this stage the beans start to swell back up and “pop open” increasing their physical size by fifty percent. When the developing point is reached the heat is turned up and the roasting is finished as quickly as possible.
“Dry” and “Wet” Roasts
A coffee roaster uses a utensil called a “trier” (it looks like an elongated spoon) to check the progress of the beans often during the roasting process. The trier is slipped into the cylinder taking a sample of the roasting beans and compared to a type sample. When the coffee has reached the desired level of roasting the heat is shut off to “check” or stop the cooking by reducing the temperature of the coffee and roasting cylinder as quickly as possible.
In the wet roast method the coffee is sprayed with water while the roasting cylinder is still revolving to cool the beans and stop the cooking.
In the dry roast method the beans are poured out of the roasting cylinder into a large colander type basket where they are stirred rapidly while air is blown through the beans to cool them down as quickly as possible to stop the cooking.
Excessive watering of coffee in and after the roasting process to reduce shrinkage is typically frowned upon. “Heading” the coffee or checking the roast before removing it from the roasting cylinder is considered a legitimate practice.
When water is used to quench the roast and stop the cooking most of the water turns to steam and does not get absorbed by the beans. However the beans do tend to swell slightly and brighten the coffee. Even though some water is used to check the roast it is still considered to be a “dry roast”.
It is doubtful that more than a handful of American coffee roasters use an absolutely “dry” roasting method – it is difficult to maintain consistent results from one batch to another and usually doesn’t provide the best possible product. The term “dry roasted” has been abused for years by coffee company marketing departments. Of course “dry roasted” coffee as described above will always make better coffee than beans that have been soaked with water but the word “dry” needs to be defined as to what exactly that means among roasters before the term can provide any real meaning or value to consumers.
Finishing or Glazing
In the old days of coffee roasting, whole-bean roasted coffee would be ‘finished’ by giving it a friction polish while it was still moist using a glazing solution. Roasted coffee dulls during handling and it was believed that a finish coating not only improved the roasted beans appearance but also preserved the natural flavors and aroma of the bean.
The fresh roasted beans were finished by putting them in a machine made out of flat-sided wooden cylinders. The machine would be filled about two-thirds full of fresh roasted coffee beans leaving enough room to allow the beans to get a good rolling motion going. A common coating used back in the day consisted of a concoction of sugar and eggs that would be added while the beans were rolling ensuring each bean got thoroughly coated and ‘finished’. Of course now days roasters regularly coat beans to add flavor and variety to their coffees.
by Andy Pea