How many of us choose coffee over tea at the cake stop?
But despite its prevalence, many of us probably aren’t familiar with the workings of the global industry that grows and processes the 8.3 million tons of coffee consumed worldwide each year. In this speech, I’m going to walk you through the processes involved in getting coffee to the consumer: Growing, Processing, and Roasting.
Coffee starts off on a fruit-bearing tree that produces coffee cherries. These cherries appear much like cherries that we are familiar with, though they have only a thin layer of pulp around a large pit, which will become our coffee beans. Like the fruit we are familiar with, they come in two principle varieties: Arabica and Robusta.
Arabica coffee accounts for roughly ⅔ of global coffee production. It is generally preferred to Robusta because of its lower bitterness and generally more pleasant, delicate flavors. Robusta, on the other hand, is much bolder, more bitter, and about 50% higher in caffeine. Both varieties are grown in high-altitude regions throughout the world, with coffee from different regions having distinct character from the others.
South America accounts for nearly half of global coffee production, and grows Arabica almost exclusively. Coffees from South America tend to have earthy, nutty, or chocolately flavors, and are often what we think of when we think of good, basic coffee. Central American coffees, despite being close geographically, tend to have lighter flavors, especially floral and fruity notes.
Across the Atlantic, many African countries produce roughly even amounts of Arabica and Robusta coffee, with Robusta grown in the west and Arabica in the east. These Arabica coffees are especially prized for the bright berry flavors that can be brought out of them when roasted and brewed correctly. The final major growing region is southeast Asia. This production is biased much more towards Robusta coffee, especially in Vietnam. Asian coffees often have character similar to south american coffees, but can also have more diverse earthy flavors and aromas similar to tobacco and leather.
Once the coffee is grown and harvested, the fruits must be processed to remove the beans and clean the coffee. The two principle methods for processing are dry and wet processing. Dry processing involves crushing the cherries, then spreading them out to dry and ferment in the sun. The fermentation process breaks down the cherry pulp and makes it much easier to remove from the seed. In wet climates where drying the cherries in the sun is not practical, cherries are crushed and rinsed with large amounts of water to remove the pulp. In both cases, the coffee is then screened for size, sorted to remove bad beans, then dried out to reduce water content in preparation for shipment and roasting.
Roasting is the final step in coffee production before it is ready to be brewed. Along with having a major impact on flavor, it is necessary in order to weaken the very hard green coffee bean and allow its flavor compounds and oils to be extracted.
Roasting is primarily done via either forced air convection or radiative heating. In both cases, the beans are very aggressively heated, generally reaching over 300 degrees Fahrenheit in a few minutes. Radiative heating is more common in large commercial applications, and uses heating elements located next to a perforated drum, which spins to agitate the beans and ensure even roasting. In forced air convection, roasting is achieved by forcing hot air through an agitated bed of coffee beans. In either case, the increase in temperature is carefully controlled to meet the roaster’s target. Along with smaller influences on the finished coffee’s flavor, roasting too fast or too slow can result in coffee that doesn’t grind, brew, or drink well.
Once the coffee reaches about 300 degrees, the beans will begin to make popping noises, called first crack, as the oils inside sublimate and fracture the bean. While this doesn’t cause the beans to break apart, it does make them much more porous, and signals that the beans can be considered finished, if a light roast is desired. Often the roasting continues past this point, to 400 degrees or more. As roasting continues, the beans develop more roasted flavors and lose some of the more delicate flavor compounds that indicate their origins. They will also begin popping a second time, which is called second crack, as the beans fracture internally even more. Roasting can continue up to nearly 500 Fahrenheit to acheive an Italian roast, after which the beans will begin to smoke and burn from the intense heat.
After the beans have reached their desired roast level, they are quickly cooled off to stop the roasting process, then allowed to rest for several hours to several days to allow them to release built-up carbon dioxide. Once roasting is finished, the beans are often ground, packaged, and sent to stores.
This process of growing, processing, and roasting coffee is continually carried out around the world, with new crops being harvested, processed, and roasted throughout the year. Thanks to these efforts, people throughout the world have an affordable and delicious drink to help energize them throughout the day for the miles ahead .
Whilst i would love to claim that the cakes pictured were cooked by me they were cooked by my partner Nicola .