Controlling Water Use
One major reason that the farmers at Finca La Senda chose to tinker with traditional processing methods was to save water, as they have a limited supply of it on the farm. They started out with a wet depulper, a fairly typical setup for specialty coffee farms in the region, and used a high-pressure stream of water to wash off the mucilage after fermentation. Like many other farms in Guatemala, they recirculated the water to reduce waste, using about 1 kg of water per kg of cherry, but they were not satisfied with the results. ‘The utilisation of water was okay, but the high pressure water was damaging the greens,’ Paolo explains.
Last year, they tried washing the coffee completely manually, putting it in a tank filled with water and stirring it with wooden paddles. Although the method was effective, it was extremely tiring for their workers.
This year, they came up with an innovative solution they call the ‘Jacuzzi’. Inside the washing tank, the water is filtered and then pumped through small holes in a tube lying at the bottom of the tank. The jets of water slowly agitate the green coffee, loosening the mucilage. ‘We aren’t looking for 100% washed,’ Paolo says. ‘If it’s not completely clean, it’s even better. The little bit left continues fermentation on the drying beds and adds flavour.’
The ‘jacuzzi’ in action: fermented coffee is poured into the tank, and gently agitated with jets of water to loosen the mucilage. Video courtesy of Finca La Senda.
The Jacuzzi requires very little water, which means that by the end of the process the water is thick with pulp. ‘You can’t recirculate it,’ Paolo says. ‘At the end, it’s like a mashed banana! So we have been focusing on how we can treat it.’
At the moment, they are using the liquid as fertiliser. ‘We filter it, add kitchen waste and ash from the cooking fire,