by ecc on Fri Apr 08, 2011 2:35 pm
Let me be the first irritating person to step in here and say... it depends.
I don't think the profile Jim describes is intended to be a generic, one size fits all profile. (please, please correct me if I am wrong Jim!) The amount of energy it takes to get any single bean roasted is variable with the bean density, and is subject to the taste goals and roast level goals mitigated by the capabilities and defects of the roaster to transfer the energy. The profile Jim describes is a certainly a useful baseline profile, it demonstrates a lot of control over each of the phases, and is relatively simple to communicate without going into a lot of the roasting "one hand clapping" ambiguities.
Márcio is roasting lower density (I assume) beans to a light roast level. He will need to control ET at a much lower temperature because the beans won't absorb high levels of heat quickly and evenly. His milestones will all occur at lower temperatures because of the slower, lower heat.
oton, I would recommend more airflow (like an 7 or 8 at 1000w), and maybe even more initial heat. The bean you are using obviously is going too hard through first, you will want to control your phases to roughly match the guidelines Jim posted. For that bean I would try cutting the heater back to 800w around 180C, and at 1st down to 600w with minimum airflow. In the long term, get some ET guidance and experiment with different levels between 250C and 290C, try different shape curves within the rough times. I find some beans like longer drying for sweetness, others prefer a longer ramp to 1c, others need a little extra baking after 1c. Each takes adjustments in all three phases to get it done.
Hoping this helps,
Todd