Coffee Mill - Page 3
In the final step of the wet milling process, coffee is dumped into a clean fresh water tank in which the inflow and outflow of water remains constant for a minimum of twenty four hours and a maximum of forty eight (Pic 25, Pic 26, Pic 27, Video 11 and Video 12). This process helps to homogenize coffee beans by reducing the amount of chlorogenic acid present inside the beans. Unripe fruit has a much higher content of chlorogenic acid that ripe fruit does. The amount of chlorogenic acid is reduced from the coffee beans, thus producing a more homogeneous, tartness-free cup. Such tartness is common in fruits where the ripening cycle has been interrupted. This process is employed as insurance, in the event that the sorting in the picking stage was inefficient, allowing the access of unripe beans to the coffee cherry receivers. In brief, our goal is to produce flawless coffee with strict quality control mechanisms, with the least amount of water possible, in order to prevent surface and deep-water contamination.
After the coffee beans have been soaked in clean water, the same need to begin the drying process as soon as possible. The more time it takes for the coffee beans to begin its drying stage; the more is the likelihood of fungus contamination and other taints that may jeopardize its quality. The first drying stage consists of draining the water from the parchment coffee by passing the coffee through a perforated steel sheet, separating the coffee beans from the water (Pic 28). Subsequently, coffee beans are transported and deposited in pre-drying machines in order to reduce the moisture contents of the beans, by osmosis, to thirty percent (Video 13, Pic 29, Video 14 and Video 15).
Once the coffee beans have reached a moisture content of thirty percent, the final and most critical phase in the drying process begins. Fluctuations in temperature tend to cause cup defects; therefore, during this final stage, furnace temperature has to remain constant at fifty degrees Celsius. We manage to maintain temperature constant, by employing a strict monitoring control system of the furnace temperature every twenty minutes (Pic 30). While monitoring furnace temperatures, we manage to collect data in order to graph the fluctuations in temperature from start to finish of every single batch. The final drying of coffee is performed either in drum-roll drying machines or on coffee patios (Video 16, Pic 31, Video 17, Video 18 and Video 19). In this stage, the moisture contents of the coffee beans should be reduced from 30% to 12%. Once the coffee beans have reached an optimum 12%, the same enter a stabilization phase, in which all the bean should homogenize through osmosis and reach the same moisture content. This process consists in leaving the coffee beans all together and untouched (Pic 32 and Pic 33), to rest for twelve hours before being stored in a warehouse (Pic 34).
Allowing dried coffee beans to rest, homogenizes the batch to an even appearance and texture (Pic 35).
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