Where do coffee trees grow?
Coffee trees grow between 5 to 10 meters in height. There are just two types of coffee beans, Arabica and Robusta, for more info about this, read this blog post. Most of the world’s coffee grows within an area known as the “Bean Belt”, the area around the equator between the Tropics of Capricorn and Cancer. This region includes parts of South and Central America, Africa, Asia, and the Middle East. Coffee is grown in more than 50 countries but most of the world’s coffee is produced by just 5 of them.
How do coffee berries become beans?
Once the berries are ripe, they are handpicked, selective picking is used to produce higher grade coffee because the cherries are picked at their ripest, this is often the reason why certain coffees are more expensive.
Two methods are primarily used to process coffee berries.
Wet or washed process
The flesh of the cherries is separated from the seeds and then the seeds are fermented by being soaked in water for about two days. This softens the mucilage, which is a sticky pulp residue that is still attached to the seeds. Then this mucilage is washed off with water.
Twigs and other foreign objects are separated from the berries and the fruit is then spread out under the sun on concrete, bricks, or raised beds for 2–3 weeks and turned regularly for even drying.
Green beans to a coffee roastery
The term “green coffee bean” refers to unroasted mature or immature coffee beans. These have been processed by wet or dry methods. When immature, they are green. When mature, they have a brown to yellow or reddish color. The origin and area that the beans were grown in will determine what kind of flavor it will have and what roasting technique will be used, nonvolatile and volatile compounds contribute to the flavor of the coffee bean when it is roasted.
How is coffee roasted?
The most common roasting machines are drum and hot-air roasters.
Some coffee roasters use names for the various degrees of roast, such as “House Blend” or “Cafe Roast”, for the internal bean temperatures found during roasting. Recipes are known as “roast profiles” that indicate how to achieve flavor characteristics. Any number of factors may help a person determine the best profile to use, such as the coffee’s origin, variety, processing method, moisture content, bean density, or desired flavor characteristics.
As the coffee absorbs heat, the color shifts to yellow and then to increasingly darker shades of brown. During the later stages of roasting, oils appear on the surface of the bean. The roast will continue to darken until it is removed from the heat source. Most roasters use a combination of temperature, smell, color, and sound to monitor the roasting process.
There are two events called “cracks” that roasters listen for, at approximately 196 °C (385 °F), the coffee will emit a cracking sound. This point is referred to as “the first crack,” marking the beginnings of a very “light roast”. At the first crack, a large amount of the coffee’s moisture has been evaporated and the beans will begin to increase in size. When the coffee reaches approximately 224 °C (435 °F), it emits a “second crack”, this sound represents the structure of the coffee becoming brittle and fracturing as the bean continues to swell and enlarge from internal pressure. If the roast is allowed to progress further, it begins to take on the characteristics of the roasting process and loses the characteristics of the coffee’s origin.