After 2 months of studying and roasting weekly, I'm finally getting great 1/4 pound roasts from my Behmor. Early on, I began to realize that the Behmor's preprogrammed profiles for 1/4 pound roasts are way off. I suspected that I was getting to first crack too fast. As I was preparing an experiment to start my next roast at 75% power, I stumbled upon a great post on this discussion board by JimF titled "Designing roast curves for the Behmor 1600 Plus." In that post he outlined an awesome procedure for roasting 1/4 pound batches on the Behmor. Here's the procedure with some minor modifications.
1. Load the drum with beans. Insert the chaff tray but keep the drum out. Preheat to 200 degrees by pressing 1/4, Start. Quickly remove the chaff tray, insert the loaded drum, and replace the chaff tray.
2. For 1/4 lb of beans, press 1/2, P3, C, Start, P4. This places the machine at 75% power in manual mode.
3. At 9:00 on the countdown timer (5:00 into the roast), press P5 (this offsets the affect of the afterburner, which comes on at 5:00 with these settings)
4. At 8:15 on the countdown timer (after 45 seconds), press P4
5. At first crack, press P3
6. At 14:00 * 0.25 = 3:30, press Start to prevent the Behmor from helpfully shutting off and ruining your beans!
7. Press Stop when the roast is at the desired point. Wearing gloves, quickly remove the chaff tray, remove the drum, and press 1/2, Cool to start the cooling cycle. Immediately begin the cooling procedure. Cool beans in as close to 4 minutes as possible.
WOW! I'm getting great roasts! I suggest you try this procedure yourself. If you do, let me know what you think.
So far, I've only roasted beans that Behmor recommends for preprogrammed profile P1 or P2, which includes all centrals, Peruvian and Colombians, using this procedure. Now that I understand the strategies for getting around the the Behmor's built in obstacles, I've mapped out a plan for tackling other coffee beans (i.e., beans that Behmor recommends for preprogrammed profiles P3 to P5), but haven't tried them out yet.