From Bean to Cup: The Story of Coffee Production

Coffee trees — which tend to grow in tropical areas about 3,500 feet above sea level, will bear fruit, or coffee cherries, every year for approximately 25 years until they need replanting. When they are bright red, they are ready to be picked.

There is typically one coffee harvest per year, with the exception of certain countries, such as Colombia, where there is a main and secondary crop. Harvest time varies depending on location. North of the Equator, harvest takes place between September and March, and south of the Equator, between April and May. Coffee is either strip picked (all the cherries stripped off the branch at once), or selectively picked (plucked individually by hand based on degrees of ripeness). Coffee pickers are paid by the basket, and can harvest six to seven baskets a day.

Once picked, coffee cherries must be processed immediately, meaning that the fruit of the cherry must be removed, leaving the seed, or "bean." There are three distinct methods of processing: wet processing, dry processing, and semi-dry processing.

Wet, or washed, processing is popular in many Latin American countries, and can either be done by hand or using a machine. First, beans are sorted in water based on density; bad or unripe fruit will float, while quality cherries will sink. Then, four layers — the outer skin, pulp, parchment (or tough skin), and silver skin — are hulled and removed. The process helps to create a coffee that's clean and bright.

Semi-washed processing — also known as semi-dry processing — is common in countries such as Indonesia, Papua New Guinea, and Brazil; beans are picked, rinsed, then laid out to only partially dry, resulting in a flavor that's less acidic and heavier in body than wet processing. Coffee is then milled to remove what's left of the fruit, either using simple millstones or advanced machinery.

While still green, coffee is shipped from mills to roasting plants in jute or burlap sacks. After it's heated to a high temperature, coffee expands in size, loses 20 percent of its weight, and develops a dark, toasty aroma. Unlike single-origin coffees, roasting of coffee blends may be manipulated slightly from year to year in order to maintain a consistent flavor year over year.

Each roasting plant has tasters who grade coffee samples from quality control. These tasters perform routine calibration exercises to ensure their palates are judging coffee by the the same standards across the board.

Before coffee is brewed, it must be ground to facilitate the transfer of flavor. The size of the grind will strongly affect the results. Typically, coffee is sold whole, since ground coffee deteriorates faster than whole bean coffee. Certain types of coffee, however, such as flavored coffee, must be ground prior to sale due to the way they are manufactured.