Join the beta
Menu
Join the beta

Chapter III

Processes

Between the tree and the roaster, the fruit has to come off the seed. How that happens changes the cup more than most people guess.

  1. 01

    In the field

    • Selective Picking Picks only cherries at peak ripeness, with pickers rotating among the trees roughly every eight to ten days.
    • Strip Picking Takes ripe and unripe fruit off the branch together in one pass, by hand or machine, much faster than selective picking.
    • Cherry Flotation Sorting Floats cherry in water so light material such as leaves, twigs and tree-dried fruit rises off while heavier cherry sinks.
    • Cherry Ripeness & Brix Sorting Reads the sugar (Brix) in cherry juice with a refractometer to time picking or to accept, reject or separate lots by ripeness.
    • Export Packaging Bags milled green coffee for shipping in plain jute, jute with a hermetic liner, or vacuum packs, trading cost against protection.
  2. 02

    Removing the fruit

    • Washed Removes skin and pulp, ferments the mucilage off the beans, then dries. The most common process and often linked to the highest quality.
    • Natural Dries whole cherry in the sun on patios or raised beds, then hulls off the dried fruit, used for about 90% of Brazilian arabica.
    • Honey Removes the skin but dries the beans with some or all of the mucilage left on. Often sweeter, mellow cups, with Costa Rica a pioneer.
    • Wet-Hulled Hulls parchment while still semi-wet (30-35% moisture), then dries the bare bean, used in Sumatra, Sulawesi, Flores and Papua.
    • Mechanical Demucilage Scrubs mucilage off the beans by friction in a machine instead of fermenting it off, using less labor and water than tank washing.
    • Double Washed Runs two fermentation and washing stages instead of one, a first tank fermentation then a second soak in fresh water, as in Kenya.
    • Kenya Double Fermentation Kenya's two-stage wash: a 24-36 hour tank fermentation, then a 12-24 hour soak in fresh water before drying on raised beds.
    • Semi-Washed A loose label for methods that fall between wet and dry processing, mainly pulped natural (honey) and wet-hulled coffees.
    • White Honey The lightest honey grade, closest to washed coffee on the mucilage spectrum. Grade names are producer-assigned and not standardized.
    • Yellow Honey Part of the mucilage is removed mechanically and the rest left on, with drying in about eight to ten days. Grade names are producer-assigned.
    • Red Honey Retains roughly half to three quarters of the mucilage, with drying in about twelve to fifteen days. Grade names are producer-assigned.
    • Black Honey Dries with all of the mucilage left on, taking around thirty days. The honey grade closest to natural. Grade names are producer-assigned.
    • Pulped Natural Brazil's version of honey processing: skin removed, beans fermented and dried with the mucilage left on, no washing step.
  3. 03

    Fermentation

    • Anaerobic Fermentation Ferments coffee with oxygen reduced or excluded, in sealed tanks or bags, favoring lactic acid over alcohol.
    • Extended Fermentation Runs fermentation far longer than the usual 12-36 hours, often 72 hours or more, chasing deeper fruit notes at the risk of over-fermentation.
    • Koji Fermentation Sprays koji mold spores, as used for sake and miso, onto cherries during fermentation, aiming for more body and refined fruit character.
    • Wine Process A trade label for natural coffee fermented as whole cherry for an extended period before slow drying, aiming for fruit-first, winey cups.
    • Anaerobic Washed Ferments pulped beans, still coated in mucilage, sealed with little oxygen, then finishes them as a washed coffee.
    • Anaerobic Natural Ferments whole cherry sealed with little oxygen, then dries it as a natural coffee.
    • Anaerobic Slow-Dry Follows sealed anaerobic fermentation with a deliberately long drying period on beds, as in Elida Estate's slow-dry lots.
    • Carbonic Maceration Ferments fruit under carbon dioxide, a winemaking technique that suppresses aerobic respiration and favors fermentative metabolism.
    • Thermal Shock Briefly heats cherry or parchment (about 85 C) and then chills it in cold water to cut unwanted microbes before controlled fermentation.
    • Yeast-Inoculated Fermentation Adds chosen yeast strains, sometimes wine or beer yeasts, to the fermentation instead of relying on the wild microbes present.
    • Lactic Fermentation Anaerobic-style ferments that lean on lactic acid formation, a route linked in trade writing to more intense flavors.
  4. 04

    Co-fermentation

    • Co-Fermentation Adds fruit, spices or herbs to the fermentation alongside the coffee, a practice now contested on transparency grounds.
  5. 05

    Drying

    • Patio Sun-Drying Spreads coffee on a flat concrete or brick patio in the sun, raked by hand through the day to dry evenly.
    • Raised Bed Drying Dries coffee on elevated mesh beds that let air move through and beneath the layer, drying more evenly than a patio.
    • Mechanical Drying Tumbles coffee in a heated rotating drum, or another mechanical dryer, so drying takes hours instead of days.
    • Shade / Slow Drying Dries coffee on beds or patios shielded from direct sun, which reduces UV exposure during drying.
    • Parabolic Dryer Drying Dries coffee inside a tunnel-shaped, plastic-covered structure that traps solar heat, speeds drying and keeps rain off, without burning fuel.
  6. 06

    Milling and sorting

    • Parchment Resting Holds dried parchment in bags for weeks or months before dry milling, which can let moisture equilibrate and may improve the cup.
    • Wet Milling (Pulping) Runs cherry through a pulping machine (disc, drum or screen type) to strip the fruit before fermenting or washing.
    • Dry Milling Hulls dried coffee to remove parchment or dried fruit layers, with optional polishing, before sorting and grading.
    • Density (Gravity Table) Sorting Separates beans by density using gravity separators or a catador, after size sorting and before color work.
    • Screen Sizing Grades green beans by passing them through round-hole screens measured in 64ths of an inch, such as screen 16.
    • Color Sorting Removes off-color beans by optical sorting machines or by hand, after size and density sorting.
    • Hand Sorting Has workers pick out defective or off-color beans by hand, still done where labor is affordable or employment is a goal.
  7. 07

    Ageing

    • Monsooned Exposes dried green coffee to monsoon humidity in ventilated coastal warehouses, echoing old sailing-ship voyages.
    • Aged (Green Coffee) Stores green coffee for months or years so acidity fades and flavor and body strengthen, as in Old Government Java.
    • Barrel-Aged Green Coffee Rests green coffee in empty whisky, rum or wine barrels for weeks before roasting so the porous beans pick up wood and spirit aromas.
  8. 08

    Decaffeination

Place positions: GeoNames, CC BY 4.0. Coastlines: Natural Earth (public domain).