The Art of Dry Milling: Precision in Coffee Processing
The journey of specialty coffee doesn’t end with drying on the African beds. Before our beans can be shipped across the world, they must pass through a rigorous, high-precision process known as dry milling (beneficiado seco). This stage is critical for transforming “parchment coffee” into the flawless “green coffee” ready for roasting.
At Hacienda La Florida, our dedicated processing plant in Malacatos utilizes advanced technology to guarantee absolute purity and consistency in every microlot. Here is a look inside the meticulous steps of our dry milling process.
1. Hulling (Trilla): Uncovering the Green Bean
Coffee beans are stored in a protective layer called parchment (pergamino) or, in the case of naturals, the dried cherry pod. The first step in the dry mill is hulling (trilla). Our specialized hulling machines gently crack and remove this outer layer using friction, revealing the green coffee bean inside without damaging its cellular structure.
This step must be carefully calibrated based on the bean density and processing method (Washed, Honey, or Natural) to avoid chipping or overheating the beans.
2. Screen Sorting (Clasificación por Mallas)
Consistency in bean size is vital for an even roast. After hulling, the beans pass through a series of vibrating screens or meshes (mallas) with precisely calibrated holes. This separates the coffee into different size classifications, often graded from screen size 14 up to 18 or 19.
By ensuring uniform screen size, we help roasters achieve a perfectly balanced flavor profile, preventing smaller beans from burning while larger beans remain under-roasted.
3. Density Sorting (Selección por Densidad)
Size isn’t the only metric for quality; density is a key indicator of bean development and complex flavor potential. The coffee is fed onto gravity tables—vibrating, angled platforms with forced air blowing from underneath.
The heavier, denser beans (which are tightly packed with sugars and organic acids) travel up the incline, while the lighter, less developed beans (or those hollowed out by pests) float to the bottom and are separated out. This ensures only the most structurally sound beans make it to the final stages.
4. Optical Sorting (Selección Óptica)
To achieve a true “zero-defect” specialty grade, human eyes are assisted by cutting-edge technology. Our optical sorters use high-speed cameras and sensors to scan each individual bean as it falls through the machine.
The machine is programmed to detect slight color variations—such as “black beans,” “sour beans,” or insect damage—and uses a precise burst of compressed air to shoot the defective bean out of the stream in milliseconds. This optical precision eliminates off-flavors and secures the pristine cup profile Hacienda La Florida is known for.
5. Vacuum Packaging (Empaque al Vacío)
Once the green coffee has passed all mechanical and optical sorting (and subsequent manual sorting), it is ready for export. Green coffee is a porous, living product that can easily absorb ambient moisture, odors, and lose its vibrant characteristics during a long sea voyage.
To preserve the freshness and lock in the intricate flavor profiles, we use vacuum packaging (empaque al vacío) often enclosed in protective cardboard boxes. By removing the oxygen and sealing the coffee hermetically, we pause the aging process. When a roaster in Europe or Asia opens a box of Hacienda La Florida coffee months later, it smells and tastes just as fresh as the day it left our climate-controlled adobe warehouse in Loja.
Through this uncompromising dry milling process, we ensure that the hard work of our agronomists, harvesters, and fermenters translates into a perfect, flawless cup anywhere in the world.