Our blog is back!

After some time in the digital wilderness, we are resolved to start blogging again. To start with, we thought we would start at the very beginning with our little guide to the humble coffee bean:


While the true history of the first cup of coffee is lost in obscurity, two stories about the origin of coffee as a beverage are worth sharing here.

In the first, Mohammed, ill and praying to Allah, was brought coffee and the Koran by the angel Gabriel. The coffee gave him “enough strength to unseat 40 men from their saddles”.

The second recounts a goatherd who, upon noticing his goats dancing and prancing, found that they had eaten from a coffee tree. Monks who saw this odd behaviour gathered coffee beans and made a beverage that they started using to stay more alert during long prayers.

While the true origin of coffee as a beverage is lost in the past, it did originate in Ethiopia, and was “discovered” around 850 AD. Historical evidence indicates that at first the dried fruit was steeped like tea to make a beverage; when the first beans where roasted, ground, and brewed into what we know as coffee is lost in the annals of history.

For a time, Arabs controlled coffee production by not allowing access to coffee farms by outsiders, and by heating beans before export to prevent them from germinating. An Indian pilgrim apparently smuggled viable beans to Mysore, India, around 1600 AD. Still, the Arabians controlled the flow of coffee beans to Europe until 1616, when a Dutch trader stole a coffee plant and propagated plants for the Amsterdam Botanical Gardens. Seeds from those plants were brought to numerous Dutch colonies, and soon spread throughout the tropical world.

Although it soon became the second largest commodity traded internationally (after oil), for centuries, the quality of coffee was not important. The explosion of American gourmet coffee consumption, led by Starbucks, has had a notable impact on the international coffee market since the 1990s.

Coffee Markets

While there are at least 90 species in the Coffea genus, only Coffea arabica and Coffea canephora are cultivated for commercial production. These are commonly known as arabica and robusta, respectively. Arabica originated in the highlands of Ethiopia and is grown at altitudes above 500m. Research and anecdotal evidence suggests that the best quality coffee grows above 1000m asl. Arabica has a milder and more flavourful taste and lower caffeine content than robusta, which is more resistant to insect damage and disease. Arabica requires soil that is slightly acidic (5.2-6.3pH); it can be grown on more acidic or alkaline soils, but nutrient availability may become a problem.

One major challenge for coffee production is the wide fluctuation in market price. For example, during the period from 1994 to 2004, the International Coffee Organization's indicator price for a pound of green arabica beans ranged from $0.54 to$2.22.

Coffee Processing

Most arabica coffee is processed in one of two ways: dry processing and wet processing. Dry processing is simpler; more often used in East Africa, and involves simply allowing the harvested fruits to dry in the sun intact. When they are dry, the beans are removed by a machine. Wet processing is more common in Latin America, and involves more steps. The beans are removed from the fruit, allowed to ferment to remove a slippery mucilage layer, washed, and dried.

Coffee Quality

Coffee quality may seem subjective, since it is related to how it tastes and smells, and personal preferences and sensitivities can vary widely. However, there is an increasing body of research that treats coffee quality as a quantifiable characteristic. Researchers are currently looking into which of the approximately 800 chemical compounds present in roasted coffee are linked most strongly to aroma and perceived quality, and they are finding that processing methods are crucially important. Research on coffee quality has traditionally focused on varietal and environment along with roasting processes as the largest impacts on coffee quality.

Recently, researchers have begun to look into processing as an important determinant of quality. In blind cupping tests, wet-processed coffee generally scores higher than dry processed coffee. It had been assumed that this was because wet-processed coffee had a higher percentage of ripe fruit harvested, while dry-processed had a wider range of ripeness, including unripe and overripe fruits. Processing experiments with samples of similar ripeness show that the processing method itself creates significant differences in the beans. The two main processing methods have a measurably different effect on the sugars and flavour precursors present, which in turn play a role in complex metabolic processes that the bean undergoes during processing and drying. These studies have also shown that the metabolic processes are related to germination, which starts to occur even when the period between harvest and final drying is short. Drying is also considered an important step in quality coffee production, since moisture levels higher than 12% can promote microbial growth and mycotoxin formation.

July 16, 2015 — Gary Carruthers
Tags: Blog

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