Harvest Series #6: Coffee Processing with Solar Energy

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You could say that coffee farmers have always used “solar power” to dry their beans — and you’d be right.

After picking and depulping the cherries, farmers would traditionally spread their harvested beans on a concrete or plastic patio; tending each batch for 5 to 15 days and depending on sunshine to do the drying.

Environmentally friendly, yes, but also lengthy and yielding variable results in quality due to the common interference of rainfall. Patio drying is also a very labor intensive method, requiring farmers to manually haul sacks of coffee and constantly rake the beans throughout the day.

Standard commercial dryers (which are mechanical in nature) deliver faster (36 hours) and more consistent results — but at major financial and environmental cost, with their enormous demand for non-renewable forms of energy.

After realizing just how wasteful commercial dryers are, it became clear to the partners of Cafe Solar that there was a need for an alternative solution that had the capability of producing commercial-sized and commercial-quality batches of coffee in an environmentally friendly manner.

That’s where this coffee’s innovative, 100% green-energy drying tower controlled by Co-operativa COMISUYL comes in.

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It has all the advantages of standard commercial dryers, and more, in that it dries the coffee in 24 hours (more efficient) and uses low temperature drying to preserve volatile oils (high quality), plus …

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“It is the only complete commercialized alternative energy coffee processing facility in the world,” says Derek Zavislake. He knows the process well: his social-enterprise company, Merchants of Green Coffee, is the sole trading partner for Cafe Solar in North America, and supports the co-op each year by guaranteeing the purchase of the entire premium-bean Cafe Solar output.

Some crunchy little bean-sized facts about the unique off-grid drying tower:

  • Dimensions: 6 ft wide X 24 ft long X 25 ft tall
  • Batch size: 48 quintales (48 x 100lb sacks, or 4,800 lbs total) of green beans
  • Time & temperature in the drying chamber: 24 hrs per batch, at 45-50 degrees Celsius
  • Energy source: powered by solar panels by day, and by biomass (coffee husks & local jatropha oil) by night & on cloudy days

The results? Good news for the environment, and for the co-op’s budget:

  • No forest is cut down to power the drying process
  • Only the cost is cut down — from $4.00 per 100lb bag with the conventional commercial dryers (powered by firewood, diesel, propane, electricity), to $0.40 per 100lb bag with Cafe Solar’s unique solar-powered dryer.
  • Keep checking this page: we will be writing more, step by step, about the process that brings Cafe Solar from the mountains of Honduras to your coffee cup.
  • Next Week: Great Coffee Must Settle
  • And mark your calendar: the 2014-15 harvest will be available this May!