<Tr> <Th> </Th> <Td> World </Td> <Td> 8.8 </Td> </Tr> <P> Coffee berries and their seeds undergo several processes before they become the familiar roasted coffee . Berries have been traditionally selectively picked by hand; a labor - intensive method, it involves the selection of only the berries at the peak of ripeness . More commonly, crops are strip picked, where all berries are harvested simultaneously regardless of ripeness by person or machine . After picking, green coffee is processed by one of two methods--the dry process method, simpler and less labor - intensive as the berries can be strip picked, and the wet process method, which incorporates fermentation into the process and yields a mild coffee . </P> <P> Then they are sorted by ripeness and color and most often the flesh of the berry is removed, usually by machine, and the seeds are fermented to remove the slimy layer of mucilage still present on the seed . When the fermentation is finished, the seeds are washed with large quantities of fresh water to remove the fermentation residue, which generates massive amounts of coffee wastewater . Finally, the seeds are dried . </P> <P> The best (but least used) method of drying coffee is using drying tables . In this method, the pulped and fermented coffee is spread thinly on raised beds, which allows the air to pass on all sides of the coffee, and then the coffee is mixed by hand . In this method the drying that takes place is more uniform, and fermentation is less likely . Most African coffee is dried in this manner and certain coffee farms around the world are starting to use this traditional method . </P>

Where does the acid in coffee come from