Back in March I roasted some Uganda Sipi Falls beans and reviewed them as being rather bland. I recently found a small quantity of these beans in the back of my pantry. Never one to waste coffee I decided to roast them, this time at a higher temperature.
The roast profile used for this roast was the same as the Sumatra where I start at 375, increase to 425 at four (4) minutes, and increase to 475 at six (6) minutes. My previous roast attempt started at 250, and gradually increased to 475 by seven (7) minutes. This was probably not enough heat resulting in the less than tasty coffee.
Increasing the temperature later in the roast appears to improve the ability to get a firm first and second crack. I believe this is due to the beans getting lighter as the roast progresses. The beans get lighter as they lose moisture. When the beans are lighter they "float" more in the hot air allowing more of the hot air to escape. At the start of the roast the beans are heavy and sit on the hot air not letting much air escape except for when I stir the beans with a spoon. Later in the roast, when the beans are lighter, more hot air escapes because the now lighter beans are "floating" more. To compensate, the temperature must be increased.
Anyways, after four (4) days roast this coffee was tasty. It was nutty, smooth, and not ashy at all. It wasn't quite as flavorful as the Colombian but it was a nice, tasty, daily drinker. I may be trying some more in the future.