There are many variables that play into the quality of the final cup of coffee that we all enjoy. In some of our previous blog posts, we’ve discussed how brewing can greatly alter how a coffee tastes. But before the final brew, there are a lot of other things to consider. This post is part one of a two part series about the role that coffee harvest and roast freshness play into the final product. In this part of the series, we’ll briefly discuss some of the ways that coffee harvest influences the quality of coffee.
To begin, it’s important to recognize that coffee is an agricultural product. Like other fruits, coffee must be harvested at the correct time in order for it to be properly enjoyed. If coffee is harvested too soon, it is underripe, and lacks the sweetness and complexity that time and photosynthesis impart on it. Conversely, if a coffee is harvested too late, it becomes overripe, often leading to unpleasant notes of over fermentation.
But what happens in the coffee’s life cycle, and when, to cause these quality issues?
PICKING & CHERRY RIPENESS
How long a coffee stays on the tree is vital to its development, and so is the color that the cherries are picked at. Varieties of coffee that are red are often picked at a stage often referred to as “sangre de toro,” or “bull’s blood.” When many varieties of coffee reach this rich hue of red, it is clear that they have developed to the point of ripeness and are ready to be harvested. However, not all coffee has red skin, so this doesn’t apply to all coffees. For example, some varieties are pink, while others are yellow. Pickers use varying levels of intensity of color to know when is the best time to pick a coffee.
Once coffee cherries are harvested, they must be sorted to ensure that underripes, overripes, and foreign matter such as twigs are removed from the ripe cherries. Cherries are often sorted with water, as ripe cherries sink due to their density, while coffees that float, known as “floaters,” do not. Once the cherries are sorted, they are purposed based on their classification/quality. Ripe cherries flow through the additional following steps, while the “floaters” are often sent straight to patios.
Once cherries have been sorted, they are processed using an array of methods. If a coffee is washed or honey process, it is depulped, a process by which the skin of the cherry is removed before fermentation. Natural processed coffees leave the skin on the cherry, and forego pulping. Whether the coffee is pulped or not, it then undergoes a fermentation process. The tanks are filled with water, which helps remove the mucilage (the sticky fruit that surrounds the coffee bean) before the coffee is dried. Many natural processed coffees little to no water, depending on whether they are pulped or dry naturals, allowing the fermentation to happen inside of the cherry. If fermentation happens too quickly or is too drawn out, the quality of the coffee can suffer. From not tasting well developed to tasting over fermented, there is a lot that can go wrong in this stage of any given coffee’s life cycle and shelf life.
Once the coffee has undergone some type of fermentation, it is dried. Common forms of drying are on raised beds, patios, and in guardiolas (large agricultural driers). As with the other stages, timing is crucial when it comes to drying, and if note done properly, the quality, and especially the shelf-life, are greatly impacted. If you don’t dry a coffee long enough or fail to turn it over frequently during drying, you risk having too high of water activity. High levels of water activity promote the growth of things such as bacteria and mold, which is not a desirable outcome. If you dry a coffee too long, you risk a shorter shelf-life due to potentially very low moisture content.
Though this list was brief, these are a few of the many ways that coffee harvesting and processing influence the final product. Stay tuned for our next post in this series, which will explore how roast freshness and storage influences the final cup! And to try some of the fruits of the harvesting labor, click the button below to shop our Farm to Cup coffees with free carbon neutral shipping.
Hoffmann, James. The World Atlas of Coffee: From Beans to Brewing: Coffees Explored, Explained and Enjoyed., 2016. Print.