Roasting decafs is difficult for a number of reasons. All the usual signs of roast development (color, volume and time of cracks, chaff, aroma) are missing or muted.
● Decafs already start out dark, so color is tough to determine.
● Decafs are best roasted with lower heat than regular coffee as they start out with lower moisture content and damaged cellulose from processing.
● Once first crack is reached, it is important to lower the temperature even further otherwise they will reach second crack faster than one can control.