The Coffee Bean Harvesting and Processing
Coffee is one of the most popular drinks in the world, enjoyed by millions of people every day. We will explore the fascinating world of coffee bean harvesting and processing.
1. Harvesting process
To enjoy a good cup of coffee, just like with many other fruit trees, we must wait for the coffee cherries to ripen. The taste of the coffee is determined by the sugar levels in the cherries, which are at their peak when the fruit is fully ripe. This is why coffee beans that are harvested when they are fully ripe are more expensive compared to those harvested when they are still young.
There are two methods of harvesting coffee: manual and mechanical. Manual harvesting suits farms with challenging terrain, while mechanical harvesting is more appropriate for larger coffee farms.
The coffee-growing regions are divided into two hemispheres based on their distance from the equator, and most coffee harvests occur once a year. However, coffee beans do not ripen immediately and instead mature gradually over a period of about three months. The harvest of regular Arabica coffee typically occurs about 1 to 2 months before the Robusta coffee harvest. Some countries, located in both hemispheres, may have an additional small harvest crop.
In the northern hemisphere, the coffee harvest typically takes place from late winter to early summer, while in the southern hemisphere, it occurs from late summer to early winter.
Since coffee is typically harvested only once a year, the taste of the coffee may begin to deteriorate by the end of the year as it becomes older. For instance, coffee grown in the Gia Lai and Kon Tum areas of Vietnam is usually harvested between October and December, and then processed and stored for an additional two months to stabilize the flavors. This means that it takes nearly four months for new coffee to become available, typically around March or April.
Understanding the coffee harvesting and processing timeline can help explain why the taste of coffee may decline towards the end of the year. It can also help consumers make informed decisions about when to buy coffee based on the season in which it was grown.
2. Preliminary processing
To preserve the flavor of coffee beans and increase their shelf life, pre-processing is necessary. The extent to which the taste and aroma are retained depends on the specific processing method employed.
This article will provide a brief overview of the three primary and most popular processing methods: the natural or dry process, the washed process, and the honey process (also known as the pulp/honey process)…
2.1.Preliminary dry process (natural/dry process): coffee beans are left to dry in the sun for approximately one month. The beans are stirred regularly until they reach the desired moisture level. This process helps to convert the sugar in the fruit into coffee beans.
To avoid contamination of the coffee with soil smell, it is recommended to dry the coffee beans at a distance of around 50cm from the ground. If the coffee is tainted with a soil smell, it will produce a musty and earthy aroma when brewed.
Strengths: coffee will retain the most sugar so coffee beans will have the most decadent flavor in this preliminary processing.
Weaknesses: only suitable for places with a lot of sunshine, challenging to do industry, and expensive if done right.
2.2. Fully-Washed process: involves rubbing the skin and flesh of the coffee fruit, leaving only a small portion of the fruit and the husk of the coffee bean. The beans are then soaked with enzymes and left to ferment for 12 to 36 hours. Finally, the beans are washed and dried or left to dry. This process helps the coffee beans reach the required moisture level faster, thus reducing the pre-processing time.
Strengths: the cheapest of the three techniques, investment on an industrial scale is possible.
Weaknesses: The taste is not as rich as dry preliminary processing. The water source must be appropriately treated when it is finished processing. Otherwise, it will pollute the land.
2.3.The honey/pulped process: is a primary method that combines the above two methods. Coffee cherries are rubbed but still retain a part of the mucus on the fruit. Depending on how much of the pulp and slime is removed in the coffee fruit, there will be different names, such as Black Honey and Red Honey… After removing part of the fruit pulp, it will begin drying on drying racks in the greenhouse. Drying time is about 9-12 days.
Strengths: the taste of this pre-treatment will be better than the wet pre-processing but not as good as the dry pre-processing. Suitable for areas with little sunlight.
Weaknesses: Usually, the cost will be more expensive than the other two preliminary processing methods. Green coffee is easily fermented during storage.
3.Some common standards in commercial exchange
3.1. Any green coffee sold on the market must be classified according to several criteria as follows:
The number of defects in the green kernel
Sieve feces, also known as green kernel size (screen size)
Quality of taste when drinking (quality cup)
The first criterion, which is one of the most important, provides us with clarity about the quality of the finished coffee.
3.2.Two classification methods are most commonly used today:
3.2.1. SCAA (SCAA Green Coffee Classification Method) green coffee classification method. This method is superior because it explains the relationship between “error quantity” and “drinking taste quality.” However, this method still allows a certain amount of error in the coffee.
3.2.2. Brazilian / New York Green Coffee Classification Method (Brazilian / New York Green Coffee Classification Method). Green kernels must be free of defects and of the exact origin, grain size, color, and shape. This method is very accurate but takes more time to verify.
3.3. Types of Coffee in Commercial Exchange
And coffee products in commercial exchange can be divided into two basic types as follows:
3.3.1.Commercial goods： you will have a lot of choices from the popular segment to the high-end segment, the quality of the taste will also correspond to the saying: “you get what you pay for.” If you are a buyer of green kernels for sale, you need to pay attention to the most will be the price, the percentage of ripe seeds, and the place of planting.
3.3. 2. Specialty Coffee：(used to evaluate arabica beans)/Fine Robusta(used to assess robusta beans). This concept was introduced by Erna Knutsen in 1978 as follows:Particular geographical climates produce coffee beans with unique flavor characteristics called ‘Specialty Coffee.’Based on this premise, successors developed many more concepts.
3.3. 3. But in general, to be recognized as a Specialty Coffee, you must have two necessary and sufficient conditions as follows:
Eligible conditions: coffee beans must score above 80 points according to the SCA (Specialty Coffee Association) scale.
Necessary conditions:
1. Sourced from a potential farm, a good seed source;
2. Harvesting, processing, and preserving by the correct method;
3. Proper extraction (dispensing) process.
As a consumer, the origin and quality of goods are crucial factors that I will consider. The commercial interests or specialty of coffee are not as important as the taste and value for money. When buying green coffee beans, the price, percentage of ripe seeds, and place of planting should be carefully considered. Overall, I prioritize getting a good quality product that is worth the money spent, regardless of whether it is considered commercial or specialty coffee.