Harvesting and Processing Coffee 

With South America being such a huge coffee producer, they must harvest and process the coffee just so-so.  Coffee must be harvested during the dry season at which time coffee cherries are a firm and bright red color.  These cherries are picked by hand where they are all stripped from the tree that results in ripe, unripe, and overripe beans.  The other option is for the beans to be harvested with a special machine.  With this, you get selective picking along with stripping and harvesting. 

Obviously, the goal is to choose only the ripened beans, leaving the unripe beans on the tree, which would be harvested later.  Take Brazil as an example, the same tree would be harvested many times over.  Because of this, the Brazilian coffee growers usually harvest only when 75% of the crop is ready to be picked.  When the beans are pulled from the tree, many will fall to the ground but to salvage them, sheets are placed on the ground.  When done, the beans are taken from tree debris and tossed to the wind, allowing it to carry away any leaves and twigs. 

From there, the coffee beans are placed in a basket that helps the coffee producers measure them accurately.  Although some places in Brazil and other South American countries use computers, most do not.  After the beans are in the baskets, it is filled with water where the ripe from unripe and overripe are separated.  Interestingly, the beans that are overripe and unripe, along with any leftover leaves and twigs will float to the surface.  These “floaters” are typically set outside to dry and used for other types of consumption.  Keep in mind that since the unripe beans are very hard, they cannot be pulped while the other beans are with the use of pulping machines. 

Since the green beans cannot be sent through this machine, they are passed through a screen, which pushes them to the end of a barrel system, separating them from the ripe beans.  This barrel system is designed with internal pressure that can control the number of cherries being pulped.  Now, if the pressure is great enough, it could possibly pulp the green beans as well. 

For the coffee grower, it is vital that the pressure and pulping process be monitored constantly to maintain a pressure so 3% of the ripe beans are no pulped and removed from the unripe beans.  This margin or error ensures the green beans do not get pulped with the ripe beans.  Now, sometimes there are coffee beans that are covered with slippery mucilage.  These too are placed outdoors to dry.  Once done, they are sent to fermentation tanks. 

These tanks are designed to remove this mucilage prior to being completely dried.  Now, when the pulped beans are done, they are placed into special cement tanks along with water.  There, they will remain for 16 to 36 hours to ferment, with times varying depending on humidity levels and water temperature.  Prior to the beans making it to this tank, the beans that are of the highest quality are separated and fermented in their own separate tank. 

This mucilage actually consists of pectin and protopectin among others.  It is important to understand that this second substance, protopectin, is not water-soluble.  Therefore, it will hydrolyze to the pectinic acid found in the fermentation tanks.  For the growers to know when the fermentation process is complete, they will physically touch the beans to determine if the mucilage casing is still intact.  Another interesting fact about fermenting coffee beans is that the longer they are processed in the tank, the stronger they become in aroma.  This process is what decides the level of acetic, propionic, and lactic acids that end up in the coffee. 

Finally, after the beans have completed the fermentation process, they are moved to drying patios.  There, they will remain until 12% of the moisture has been removed.  Sometimes, the coffee producers will set a small amount of the beans aside to be hulled and milled.  A fascinating aspect of this entire process is that as much as 11 ounces of coffee is considered defected.  The beans that are deemed good quality, they are roasted and then cupped to label the quality.  From there, people from around the world can enjoy an amazing cup of South American coffee.