I guess I could understand this for someone roasting C-Grade who desired heavy body and low acidity. Then again you would wonder why someone like me would even be talking about this.
We were roasting today and were struggling getting efficient drying on what we believed to be a particularly good coffee. Knowing it was good made it more frustrating. At one point during a drop, a mistake in the flame setting caused the roast to begin to tail near the end of the drying phase. On the spot Ben decided to just dump it and cool it. He pulls out the old Japanese book on slow roasting and chronicles the 'delights' of the double roast. Having accomplished most of our goals for the afternoon, we decided to go for a double roast. A roast later, we had our double roast and a few new observations.
We pondered the exhaust and how the heating element was reacting with the barrel. Then it came back to the flue. Most roasters simply have an on or off while the Japanese and Taiwanese models have a variable control. Based on the discussions sparked by the double roast, we were able to ascertain we needed more efficient venting. Ten minutes of tinkering and we had a ghetto fabulous chimney fan combo increasing our drying efficiency. An ugly but entirely useful hack!
Sometimes things we know are dead ends are worth pursuing simply for the experience.