Coffee-Pedia

From Tree to Cup | What’s in a Taste? | Coffee Keeping & Brewing | Drink Dictionary | Coffee-Pedia

What’s the difference between Arabica and Robusta? How about the difference between delicate and earthy flavor? If owning or starting a coffee shop is in your future, you better know your coffee facts.

Green Beans

Arabica

Arabica coffee plants are grown at high elevations (3,000 ft to 6,000 ft), just below the frost line. Growing coffee at higher elevations produces a denser, richer bean. Because there is less oxygen, the plants grow more slowly, giving the beans a more concentrated flavor. Such high quality comes at a price: because Arabica beans are grown on mountain terrain, they are difficult to plant and harvest, and the fruit must be handpicked. This time-consuming, labor-intensive process is reflected in the coffee’s price.

Arabica plants need adequate water to flower and bear fruit. On average, an Arabica plant will bear fruit once or twice a year depending on the rainfall. If the rain is distributed evenly throughout the year, you will find the plants simultaneously producing flowers, ripening fruit and bearing fully-ripened fruit.

Robusta

Robusta coffee plants grow at altitudes below 3,000 ft. They are a heartier plant than the Arabica, being markedly more resistant to parasites and disease. They grow best on flat land at low elevations.

Since Robustas are more readily available, they are lower in price than (and have nearly twice the caffeine of) the higher quality Arabica beans. To keep costs down, many coffee companies blend Robusta beans into their coffees. For decades this was the American consumer’s only coffee choice, and many were fooled into thinking that this was what good coffee tasted like.

Armando and Greg inspecting beans

Processing

Dry Method Processing

Also known as the natural method, dry method processing is the simplest way to process coffee. The cherry is dried on the tree, or dried in the sun for about one month, after being picked. The green coffee beans are then removed from the dried, leathery fruit skins by grinding them between stones, or in special machines. Most small farms and cooperatives use the dry method of process.

Wet Method Processing

Also known as the washed method, wet method processing is more complex than dry method processing. Coffee cherries are hand-picked to ensure uniform size and ripeness. Then they are carried down the mountain in baskets or sacks, and dropped off at processing stations. The entire basket of coffee cherries is dumped into a water-filled receiving tank where stones, twigs, leaves and floating cherries are removed. (Floating cherries are either empty inside or unripe.) Next, coffee is de-pulped by cutting away the fruit that surrounds the beans. Finally coffee beans are separated by size so that they can be assigned an appropriate fermentation period.

In the critical fermentation stage, coffee beans are held in water tanks for a day or two to remove the jelly-like mucilage from their surface. Timing is everything; if the beans are fermented too long or not long enough, the coffee will be ruined. After fermentation, beans are spread out to dry in the sun, or they’re machine dried in rotary tumblers.

The large coffee estates and plantations with a commitment to quality tend to favor wet method processing since it requires few resources.

Roasting

First Crack

About two minutes into the roasting process, before the beans begin to brown they turn a golden yellow. After about eight minutes into the roast, a cracking sound, similar to that of popcorn popping, can be heard. This first crack is caused by moisture escaping from the coffee beans, and by chemical reactions which cause the beans to swell and expand. The coffee beans do not explode like popcorn, but they do increase in size by more than 50%, while at the same time being greatly reduced in weight.

During the first crack, the chaff—or papery skin—on the beans is carried away with the air moving through the roaster. At this point, the roast master must make crucial adjustments to the temperature controls of the roaster to ensure optimal roasting for each coffee origin.

Second Crack

Anywhere from one minute to three minutes after the first crack is heard during the roasting process, a second crack occurs. Most coffees reach their peak roast just as the second crack begins. At the end of the second crack, the cellular structure of the coffee is ruptured, allowing the oils to escape to the surface of the beans. It is extremely important that the roast master stop the roasting (“dumping”) at precisely the right time. Dumping seconds too soon or too late can destroy an entire batch of coffee.

Pyrolysis

Pyrolysis is the transformation of an organic substance when subjected to high temperatures. It is what causes the transformation of green coffee beans into the delicious, consumable coffee beans with which we are familiar. The heat that is generated by the roasting beans breaks down raw components like sugars, and forms the complex, aromatic compounds which contribute to the coffee’s particular flavor.

Crimson Cup's Dave E. with Godzilla Roasting Machine

Roast Levels

Light Roast Coffee

In this level of roasting, the beans begin to acquire a light sheen as the oils begin making their way to the surface. There are no visible droplets of oil, just a light gloss. The flavors of the coffee at this point are quite developed and intense, with a balanced liveliness and body. Light roasting complements a coffee whose brightness and delicate flavors you want to accentuate.

Medium Roast Coffee

Medium roast is the point in the roasting process at which visible droplets of oil begin to form on the surface of the beans. The color is just a bit darker than that of a light roast, but the spots of oil give the illusion that it is much darker. At this point, the sugars in the bean have begun to caramelize, and the coffee will have a natural, slightly sweet flavor.

Dark Roast Coffee

Dark roasted coffee can range in color from a medium chocolate brown with a satin-like luster to an almost black bean with an oily appearance. The flavor of the coffee takes on a smoky character because the sugars in the beans have started to carbonize.

Coffee Flavor Facts

This list of words was developed by the Specialty Coffee Association of America (SCAA) to help people describe the various flavors of a cup of coffee:

General Flavor Characteristics

Richness: refers to body and fullness
Complexity: the perception of multiple flavors
Balance: the satisfying presence of all the basic taste characteristics where no one overpowers another

Desirable Flavor Characteristics

Bright, Dry, Sharp, Snappy: typically used to describe African coffees
Caramely: candy-like or syrupy
Chocolatey: having an aftertaste similar to unsweetened chocolate or vanilla
Delicate: subtle flavor perceived by the tip of the tongue (typical of a washed New Guinea Arabica)
Earthy: soil-like characteristic (typical of Sumatran coffees)
Fragrant: aromatic characteristic ranging from floral to spicy
Fruity: aromatic characteristic reminiscent of berries or citrus
Mellow: round, smooth taste, typically lacking acid
Nutty: aftertaste similar to roasted nuts
Spicy: flavor and aroma reminiscent of spices
Sweet: free from harshness
Winey: aftertaste reminiscent of well-matured wine (typical of Kenyan and Yemen coffees)