Processing Coffee Beans
|The wet method||
Freshly picked coffee cherries (the name given to ripe green coffee beans) are immediately plunged into a large tank of water. At this stage, any cherries that are over-ripe or shrivelled float to the top of the water tank so that they can be easily removed.
Next, the remaining fruit is transferred to a de-pulping machine, which strips the fruit of the cherry away from the bean inside.
The coffee beans are then sorted using a series of rotating grates or sieves, sifting out the skins and grouping the beans by size. The sorted coffee beans are held in stone tanks, where they ferment for approximately 48 hours. This stage loosens any remaining pulp from the coffee bean.
Lastly, the coffee beans are processed through a series of elevated waterways, cleaning them again and making sure they’re correctly sorted by size. The water is drained away, leaving the clean coffee beans ready for processing.
|The dry method||
The coffee cherries are spread out on a large drying tray made of concrete or wire, and usually about four or five inches thick. The fruit is raked regularly to make sure it dries evenly. Once dried, the green coffee beans are stored in silos or canvas bunkers until they’re shipped.
The dry method leaves the coffee beans a darker colour than beans that have been processed using the wet method. Dry method beans also have a less uniform colour, which can indicate a lower quality of bean. Well – you can’t expect perfection from quick and cheap, can you?
How can you determine the quality of coffee?
While the wet and dry methods give different results in terms of flavour, you can’t really say one method produces better quality coffee. There are a whole range of factors that influence the quality of the final product. Coffee experts usually assess the quality of the coffee ‘in the cup’, judging it as a consumer, rather than by how it was produced.
It’s generally felt that coffee produced by the wet method will deliver coffee with a more vibrant acidity and a cleaner taste. Coffee produced using the dry method will typically deliver coffee with a rich, earthy flavour.