Coffee Hulling & Milling
How parchment and dry cherry are removed, how green coffee is prepared for export, and where polishing and grading fit in.
Dry milling
Dry milling prepares dried coffee for commercial shipment. Washed coffees are commonly hulled from parchment, while natural coffees are hulled after the fruit has dried around the seed.
Hulling
A huller mechanically removes the parchment layer or dried fruit. Equipment must be adjusted to remove the covering without excessive breakage.
Polishing
Some mills polish green coffee after hulling to remove remaining silverskin. Polishing is not synonymous with higher quality and is not used for every coffee.
Grading and preparation
After hulling, coffee can be screened by size, sorted by density or defects, and prepared into export lots. The exact sequence varies by origin, mill and commercial specification.
Continue exploring
Green coffee
Follow coffee from plant and cherry through processing, drying, milling and storage.
Green coffee →Coffee chemistry
Explore the compounds and reactions that shape roasted coffee.
Coffee chemistry →Coffee extraction
Connect grind, water, temperature, time, concentration and extraction.
Coffee extraction →Coffee Knowledge presents technical subjects as an educational reference. Terminology, grading systems and production practices can vary by country, producer, equipment and commercial context.