Coffee Bean Drying Techniques as a Potential Factor for Coffee Taste Differentiation

Drying of coffee beans has the main purpose as a process to remove the water content in the coffee beans so that the coffee beans will avoid potential quality degradation in the final processing, namely storage in the warehouse. The decrease in quality or damage (deteoration) in question is initiated by the presence of high water in the seeds, for example causing mold or triggering the presence of warehouse pests. Some species of fungi can also produce certain chemical compounds that are toxic to humans, such as the emergence of ochratoxin compounds caused by fungal attacks Aspergillus ocracheus. Fungal attack besides being able to cause toxicity in coffee can also reduce the potential for the flavor to be produced, so that aspects of drying techniques are important to consider.

The drying technique in practice can be done through drying in direct sunlight (direct sun drying), indirect drying (indirect sun drying) and mechanical drying (mechanical drying) use machine. Direct drying can use a drying floor or with tarpaulin mats, indirect drying is done using a drying table (para-para) with a cover or with a drying house which is generally equipped with ventilation. Drying using a machine is generally carried out with a convection heating system with a heating source coming from a heating furnace and blowing hot air using a fan or blower into the seed drying room. A good drying temperature according to SNI standards is carried out at a temperature of no more than 55^oC for arabica coffee beans and not more than 80^oC for robusta coffee beans.

In the processing method wet process-wet hulling or type Sumatran Process done by drying coffee beans without horns (green bean) ywhich is still wet with a moisture content range of 25-30% and low seed thickness so that the heat transfer rate in the seed drying process is more evenly distributed and water evaporation directly from the seeds so that there is no saturation which causes the seeds to require higher heat (excess) to evaporate the water. Sufficient and not excessive heat energy during drying will prevent unnecessary evaporation of volatile aroma-forming compounds (volatile), so that the potential for coffee aroma will be better and have a stronger flavor potential potensi (bold).