Coffee Roaster

Overview

The coffee roaster is a drum-type batch machine that develops green coffee into roasted beans through controlled application of heat over a 10–16 minute cycle. A perforated steel drum tumbles a 1 kg charge above a gas burner while a blower draws roast gases and loose chaff out of the chamber. The operator follows a temperature profile on a touchscreen controller, reading both bean-mass and exhaust-air probes to time the first crack and drop.

How it works

Heat reaches the beans by conduction from the drum wall and convection from burner gases. The Gas Burner fires beneath an insulated roast chamber held inside the Frame & Housing, while the Roasting Drum Assembly rotates at 50–70 rpm so that the perforated drum and internal flights lift and fold the bean bed for even color. Rotation is delivered by the Drum Drive gearmotor through a chain and sprocket.

As the roast progresses, the Airflow System system pulls heated gases through the drum perforations and into a cyclone that separates silverskin chaff before it reaches the exhaust. Airflow rate sets convective heat transfer and is a primary lever for shaping the roast curve.

The Front Face carries the charge hopper, the drop chute, and a stirred cooling tray. When the beans reach target development, the operator opens the drop door; beans fall onto the cooling tray where an agitator arm and a second blower quench them to room temperature in three to four minutes, halting roast reactions. The Control System logs bean temperature, rate of rise, and burner setting so a saved profile can be reproduced batch to batch.