Roasting
Agtron Number
A standardized measurement of roasted coffee color using a spectrophotometer, ranging from 25 (very dark) to 95 (very light). Agtron provides an objective reference for roast degree independent of time or temperature.
In Depth
The Agtron scale measures near-infrared light reflectance from ground coffee samples, with lower numbers indicating darker roasts that absorb more light. The SCA cupping protocol specifies grinding to Agtron 55-60 for evaluation consistency. Commercial roasters use Agtron or equivalent colorimeters (like Tonino or Lighttells) for quality control across batches. Ground coffee reads darker than whole bean because the exposed interior is lighter, so both measurements should be standardized.