Dry Mill, Sorting & Storing

‘Dry milling’, which is the final stage in green coffee production, involves removing the last layers of dry skin, sorting and preparing the beans for shipment. The first of these is called ‘hauling’, which is the removal of the dried sheath peeling off the bean, which in the case of coffee that has been washed as described above is known as parchment skin.
The parchment skin is removed from the coffee bean with the help of machines called hullers, which can range from simple millstones to sophisticated machines that gently abrade the coffee.
Color sorting is the trickiest and perhaps the most important of all the sorting and cleaning. Most high quality coffees are color sorted by hand, in Central America, often by teams of women. Keen eyes pick out discolored or defective beans leaving only the best for packaging. We are lucky enough to have one of the best groups of sorting women at our mill – SuBeneficio. Above is a picture of them in action. The coffee is then stored in Grain Pro – a multi-layer plastic bag made to preserve freshness and aroma for longer keeping our coffees at their best.
Most high quality coffees then go though several machines that sort the coffee by size and density of bean while removing unwanted debris that may have been mixed up with the coffee during drying in the Patios. One of these machines blows the beans into the air, separating the heaviest best that land closest , from the small beans that are propelled the furthest. Another machine is used to shake the beans through sieves, sorting them by size. A vibrating gravity separator can also be used to collect only the densest most flavorsome beans, ready for final sorting.
For storage, we have been using GrainPro at the beginning and the end of the process. When the coffee arrives in our warehouse, we immediately transfer the coffee from the nylon bags provided by the farmer into GrainPro bags in used export bags. This is done with the objective of slowing down the aging process and also to allow the beans to rest in controlled environments without drastic humidity changes. By doing this we have seen a clear difference between the endurance of the coffee in green with and without the GrainPro bag during this stage. Once we have a clear view of where each coffee lot is heading to, we decide when to process taking into account shipping date, and length of journey in order to better ensure the green coffee' shelf life. We process the coffee from parchment to green only when we have confirmed dates for shipping, and this allows us to bring the coffee at its best maturity point, still alive.
We believe that quality control means to actively control the quality, not only to assess the quality at the various stages in the process. Our quality control focuses on the preservation of the coffee bean physical, and cup characteristics. Some studies have revealed that it is of paramount importance to keep the germ alive during processing to insure that the coffee maintains its cup characteristics and also to extend the shelf life of the green coffee. We don't believe that we create the quality. It is the weather conditions, varietals, care of the farmer, and many more details that create the quality, however, we believe is our job is to preserve this quality and hence our active quality control. All the steps we take toward preserving the quality are important in achieving the overall goal of not hinder but rather benefit the beans throughout their journey from the farm to the roaster.
About us: With three generations of coffee growers in the family, Third Wave Coffee Source has sprung from a rich tradition of coffee.