Issue link: https://read.dmtmag.com/i/737343
40 STiR coffee and tea / Issue 5, 2016 (October/November) hile the quality of each coffee bean is created in the field, poor processing can ruin all that good work. This is most critical during the pulping, mu- cilage removal and drying phases when cup quality – aroma, acidity, and body – can be altered. Coffee processors constantly look for ways to preserve the quality of their beans while reducing water use and saving labor costs. Equipment manufacturers work with them to develop machinery to help the cause. It all starts with harvested cherries that arrive in a variety of conditions. With them come stones, sand, leaves, and other impurities. As it has been for ages, incoming fruit is initially sorted by hand. Workers examine coffee cherry for ripeness, pulling over- and under-ripe cherry from each lot. They also pick out the unwanted debris. Operations using mechanical sorters realize faster, more productive sorting with a far lower labor cost. Coffees may go through a second round using optical sorters to further reduce the number of defects in the end product. Focus on wet processing Wet processing, commonly used in countries where acidity is valued in the final product, requires four steps to prepare beans. Water has traditionally been central to the process but it does not necessarily help deliver brighter, cleaner, and fruitier coffee beans. A mechanical sorter or "siphon" is used to separate cherries. During this process, all cherries are submerged in water. Those that are over-ripe float to the surface be- cause they lack density and weight. These "floaters" are removed to be naturally dried in the sun. The "sinkers" are retained and move to the pulping stage where the skin and pulp are gently removed taking caution not to damage the underlying parchment and mu- cilage. The cherry is then washed and sieved to remove any pulp or skin that remains. The collected waste is returned to the farm as fertilizer. Now only parchment and sticky mucilage surround the bean. The mucilage con- tains alcohol and natural sugars and plays a key role in developing the sweetness, acid- ity and flavor profile during growth. That mucilage now must be removed, totally to produce washed coffee or partially to produce pulped natural coffee. Finessing the Flow By Dan Shryock W Pinhalense's LSC mechanical siphon sorts over-ripe cherries on the left and ripe cherries on the right A mechanical siphon at work