Once the coffee is handpicked and dried at the farm to reach an optimal, commercially acceptable, humidity level of 10-12%, what happens next? The casing around the beans, called the parchment needs to be removed, and that’s it, right? In essence, yes, but as always, there’s much more nuance to it and when it comes to ensuring excellent specialty Guatemalan coffee with impeccable taste, the devil is in the details. And we know you are d(r)ying to know what happens once the dry bean leaves the farm, so let’s take a look.

Drying the Coffee Beans

Once coffee beans are picked, we lay them on a large, open-air patio during the harvest season in Guatemala (April - May).  Some with their cherry skin (Natural Process) and some with their skin removed (Honeys and naturals) to dry for 8 to 30 days depending on the processing method. We move the coffee beans daily and watch them closely to assure slow and homogeneous drying. Did you know that the process of drying coffees directly affects the longevity of the flavor of the dried green beans? This means good practices in drying will preserve the quality of your green beans for a longer period of time.

There are three primary methods:

• Natural (Dry) Process: 

• In the natural process, the coffee cherries are laid out to dry with their skins still intact. This method allows the fruit's sugars and flavors to seep into the beans for longer periods of time, often resulting in a sweeter, fruitier cup of coffee. During this time, the cherries are raked and turned regularly to ensure even drying and to prevent mold and fermentation. This drying method is rare as it takes longer to dry (14 - 20 days on a patio, and almost a month on raised beds) and takes more work to ensure proper humidity level management. 

• Washed (Wet) Process

• In the washed process, the cherries are de-pulped to remove the outer skin and most of the fruit pulp before drying. The beans, still encased in their mucilage (a sticky, sugary layer), are spread out on the patios. This method usually leads to a cleaner, brighter flavor profile. The beans are also raked and turned regularly during this stage to ensure uniform drying. The beans can be dried in about three days. This method is used when processing our Natural Geisha.

• Honeyed Process

• Honey coffees are said to be the most “elegant” in terms of flavor. These are also washed, then de-pulped but set out to dry with the jelly-like coating. This jelly-like coating, called the mucilage, contains large amounts of sucrose (sugar) thus giving honey coffees a sweet yet bright and tangy flavor

Transition to African-raised Raised Beds

Once the initial drying on patios is completely, the beans are transferred to African raised beds in an airy barn-like structure. As the raised beds are about 3 feet from the ground, these elevated structures allow for better air circulation around the beans, which helps to further reduce the risk of mold and ensures more consistent drying. The beans are spread out in thin layers and turned frequently.

Monitoring the drying process on African raised beds is particularly beneficial for maintaining the quality and integrity of the beans. The improved ventilation helps in achieving the desired moisture content more uniformly across all the beans. This stage can last anywhere from several days to a couple of weeks, depending on weather conditions and the specific requirements of the coffee.

Once the coffees are dried at the farm and reach the needed humidity levels for perfect roasting (The proper moisture content for dried coffee beans is typically between 10% and 12%), they are sent to a dry mill to be prepped for export as green beans and in-house roasting. Most coffee farms do not own their own dry mills due to the expensive machinery required.

Let’s Talk About Price

For commercial use, coffee bean processing machinery can start at around $20,000 for small-scale operations and go up to over $500,000 for industrial-level processing, something that companies like Starbucks would require. The industrial-level machinery comes with more advanced features such as dehulling, grading, sorting, cleaning, and packaging the coffee beans. Additionally, it includes advanced technology for quality control. Not only is the machinery expensive, but its upkeep is costly too. As a small specialty roastery in Guatemala, I can tell you that breakdowns do happen. They are never fun, nor are they cheap. Taking coffee to a dry mill for processing can be cost-effective for smaller farms and roasteries, and it also allows access to better machinery to ensure quality.

The First Step: Hulling

At the dry mill, coffee beans undergo several crucial processing steps, with the first being hulling. This process involves removing the parchment layer, a papery, thick fibrous shell that becomes hardened during the maturation of the plant and dries out once the coffee beans are dried. The parchment layer also impacts the size and weight of the bean. When the beans are sent through a hulling device, all of the parchment is removed, leaving the tidy, shiny green beans ready for further processing.

The Second Step: Density Sorting

After the initial hulling process, the coffee beans undergo density sorting, a crucial step in ensuring the highest quality beans proceed to the next stage of processing. This step helps in eliminating low-density beans and removing debris and rocks, significantly impacting the overall quality of the final product.

The Final Step: Color Sorting

The last crucial step in the dry milling process is color sorting, a sophisticated method to ensure only the highest quality coffee beans make it to the market. In this step, a color sorter removes any remaining defects, such as dark-colored beans, ensuring the coffee is free from imperfections. This meticulous process ensures that the coffee meets Specialty Coffee Association (SCA) standards and is of the highest quality.

Understanding what happens to coffee after it is dried at the farm helps us appreciate the intricate process involved in producing high-quality coffee beans. Each step, from drying to milling, plays a vital role in ensuring that the coffee (whether as a coffee supplier or as a home buyer) you enjoy is of the best possible quality. By using advanced machinery and precise methods, dry mills help maintain the standards that coffee lovers expect from their favorite brew.