Though each auction day is loud with bidding for green coffee, nothing sets the final value until the beans have been roasted. Buyers see sacks of green seeds, but it’s the roasting techniques that decide the flavor profiles they’ll taste.
Drum roasting, the old method, spins beans inside hot cast iron. It gives a thick body and smoky edge. Air roasting, the newer trick, lifts beans on hot air. It’s faster, cleaner, and leaves no scorched skin. The two paths shape the cup in different ways.
Drum heat hugs beans, smoky bodies bloom; air lifts them pure, clean cups shine.
Drum machines lean on conduction. Beans touch hot metal, heat shoots in fast, and sugars turn into caramel notes. Fluid-bed rigs use convection. Hot air swirls around every bean, so heat spreads evenly and keeps flavors bright. Auction roasters often mix both styles. They start with conduction to dry the beans, then switch to convection to finish the roast. That balance keeps batches the same from bag to bag. Judges hate surprises.
Tiny dials matter. Roasters track time, temp, and airflow on computers. Beans ride on little air puffs to stay clean. Stones get sucked out by destoners so cups stay pure. Sustainable techniques are increasingly important as consumers seek higher quality and ethical coffee.
After roasting, beans rest five to ten days. Gas escape occurs as carbon-dioxide seeps from the cellular matrix, a critical pause so flavors settle before cupping. Gas escapes, taste settles, and the lot is ready for cupping. Teams sniff, sip, and score. A single burnt edge can slash the price.
Master roasters know each bean’s story. High-grown beans need less heat. Soft, wet beans need more care. A shift of two degrees can flip fruit notes into dull ash. Yet auction sheets rarely list the roaster’s name. Buyers praise farms and varietals, but the roast stays backstage. To coax maximum flavor from every cell, the roaster must orchestrate 800 to 1000 flavors which bud inside the tiny matrix during the last minutes of roast.
Some firms now use Loring Smart Roast rigs. These machines stir and heat with air only, cut smoke, and save power. The trend is growing, though quietly.
In the end, green beans cost cents, roasted beans earn dollars. The hidden weapon is not the soil or the farm. It’s the precise roast that locks in value.
