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Sustainability
Cafeology
Drying

Mechanical dryer with a walkway for sampling
and numbered doors for each compartment

The mechanical dryer is like a giant tumble Every day, the furnace is
dryer. Essentially, it is a large horizontal metal emptied of ash (which is

drum with 8 separate compartments, reaching a added to the pulp destined
maximum capacity of 60 sacks (45 kg per sack). for cattle pastures) and the
The automated drum rotates constantly and is flame ignited. Once up to
attached to a furnace that blows warm air temperature, the predried
consistently through the tumbling coffee to coffee sitting in hoppers can
evaporate moisture. Combustion is indirect, so be dropped into the dryer
the air does not directly touch the flame, compartments. Each batch is
reducing the smoke that would alter the coffee noted and then sampled
flavour. every hour or so for moisture

The furnace is temperature controlled via a and density.
computer that automatically adds reused coffee Here, a few 100 grams are
husks into the furnace to keep the temperature taken from a compartment
at a constant 50-52°C. The constant temperature and put through a small
is crucial for consistent drying as well as keeping sample huller. This huller
the beans alive. The air temperature running removes the hard parchment
through the drum (and the coffee) is 30°C lower from the coffee and allows
than the furnace, which works out at 20-22°C. for moisture and density

Subjecting beans to temperatures exceeding checking inside specialised
35°C kills the embryo within the bean causing equipment. JULY/AUGUST. 2024 | ISSUE 37
deterioration in quality before they have had a Visually, you can see how dry
chance to be shipped. Keeping beans alive keeps coffee is by colour change:
the coffee fresher for longer until a roaster white (soft to the touch) is

roasts the coffee and kills the embryo anyway. high moisture, dark jade as it

www.beveragestandardsassociation.co.uk