page_title: Coffee production
section_title: Cleaning and sorting
hierarchical_section_title: Coffee production / Milling / Cleaning and sorting
caption_attribution_description: Workers at Ambassa Enterprises, a coffee buyer and exporter based in Addis Ababa, sort the beans for export. Ambassa is run by Geoffrey Wetherill, a Lancastrian who arrived in Ethiopia during the Second World War. He got a taste for the country and the coffee, and returned soon after to establish Ambassa, now one of Ethiopia's leading coffee exporters. Geoffrey is enthusiastic about the Ethiopia Commodity Exchange, which was developed thanks to UK aid funded research: &quot;It's certainly improved things here,&quot; he says. &quot;And we are seeing a better grade of coffee now.&quot; DFID supported two leading research institutes who were tasked with finding a solution to Ethiopia's inefficient food and commodity markets. The UK aid funded research recommended setting up a commodity exchange and helped to design the warehousing, logistics and payment systems that the exchange uses today. The exchange helps to boost exports and secure a better deal for farmers and consumers. More information: &lt;a href="http://www.dfid.gov.uk/ecx" rel="nofollow"&gt;www.dfid.gov.uk/ecx&lt;/a&gt; Photo: Pete Lewis/Department for International Development
context_page_description: Coffee production is the industrial process of converting the raw fruit of the coffee plant into the finished coffee. The coffee cherry has the fruit or pulp removed leaving the seed or bean which is then dried. While all green coffee is processed, the method that is used varies and can have a significant effect on the flavor of roasted and brewed coffee. Coffee production is a major source of income for 12.5 million households, most in developing countries. By adding value, processing the coffee locally, coffee farmers and countries can increase the revenue from coffee.
context_section_description: Most fine coffee goes through a battery of machines that sort the coffee by the density of bean and by bean size, all the while removing sticks, rocks, nails, and miscellaneous debris that may have become mixed with the coffee during drying. First machines blow the beans into the air; those that fall into bins closest to the air source are heaviest and biggest; the lightest (and likely defective) beans plus chaff are blown in the farthest bin. Other machines shake the beans through a series of sieves, sorting them by size. Finally, a machine called a gravity separator shakes the sized beans on a tilted table, so that the heaviest, densest and best vibrate to one side of the pulsating table, and the lightest to the other.
  The final step in the cleaning and sorting procedure is called color sorting, or separating defective beans from sound beans on the basis of color rather than density or size. Color sorting is the trickiest and perhaps most important of all the steps in sorting and cleaning. With most high-quality coffees color sorting is done in the simplest possible way: by hand. Teams of workers pick discolored and other defective beans from the sound beans. The very best coffees may be hand-cleaned twice (double picked) or even three times (triple picked). Coffee that has been cleaned by hand is usually called European preparation; most specialty coffees have been cleaned and sorted in this way.
  Color sorting can also be done by machines. Streams of beans fall rapidly, one at a time, past sensors that are set according to parameters that identify defective beans by value (dark to light) or by color. A tiny, decisive puff of compressed air pops each defective bean out of the stream of sound beans the instant the machine detects an anomaly. However, these machines are currently not used widely in the coffee industry for two reasons. First, the capital investment to install these delicate machines and the technical support to maintain them is daunting. Second, sorting coffee by hand supplies much-needed work for the small rural communities that often cluster around coffee mills. Nevertheless, computerized color sorters are essential to coffee industries in regions with relatively high standards of living and high wage demands.
caption: Ethiopian women sort coffee beans at a long table.
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