Processing

Immediately after the  harvest  its time for processing. There are two techniques::

Dry Method - With this simple and inexpensive method, the fruits are spread in the sun to dry. During the 7 to 10 day period it takes to dry,  they are stirred regularly until the moisture comes down to 11%. The berries darken and harden while the coffee beans remains imprisoned inside. They are completely dry when you hear a hitting sound while you shake the berries.

Liquid Method -
The main difference between dry  and liquid method is that for the liquid method, the seeds are separated from the pulp of the fruit within 24 hours from the harvest using special machines with rollers or discs. They are then placed in tanks for 12 to 48 hours, where the last parts of the pulp that are stuck on the seeds are fermented and removed. Finally, they are dried by exposing them to the sun  or with air drying machines.

The fruits are fermented in machines
They are left in the sun to dry out

 
When the fruits are dry, all the remaining seed coat is removed mechanically (called peeling method). Sometimes the grains are polished to remove a silver membrane and be more visible. Finally the beans are classified by size, shape and color. The classification is done either by hand, as they pass over a conveyor belt, or an air machine that separates the lighter grain from the heavier grain. The coffee is packaged raw (green coffee  beans) in burlap bags or sisal, whose weight is sixty or seventy pounds. About 7 million tons of green coffee beans  are traded globally each year.




Roasting

The roasting is the most sensitive phase throughout the course of processing the coffee. The raw coffee is heated gradually in roasters that have the capacity to hold from 5 to 240 kg. In twenty minutes the coffee temperature has reached 250 degrees Celsius.The stirring in the drum is necessary  so the coffee doesn’t burn.


The beans start to turn yellow and much of their moisture evaporates. After  about 8 minutes the beans make the first "crack" and double in size. At 200 degrees they acquire a deep brown color, as the proteins and sugars  are released which leads to caramelization. The physio-chemical reaction «de Maillard» or pyrolysis, is what creates the impressive flavor and aroma of coffee.  A second "crack" sounds 3 to 5 minutes later, when the process is complete.


The roasting of coffee is considered an art. The coffee roaster’s  talent lies in his ability to use his hearing, sight and smell to judge when is the exact moment where you should stop roasting. Roasting time affects the color and flavor of your coffee, so the procedure depends on the desired type of coffee you want to drink. “Drip coffee" usually requires a dark-brown roast, while "Americano"  requires a medium brown roast. “Espresso” is one of the darker coffees.

Nowadays, the roasting process has benefitted from significant technological progress. In large production units computer systems control the whole process. But the human factor remains critical: The coffee roaster master is the one who determines the degree of roasting and color of the grains. This skill requires  great experience, because no one is born a coffee roaster master!





















The roaster turns green and unripe coffee beans into aromatic grains which are then sold in Coffee Shops



Before and After: Green and Roasted beans