Gene roasting profile

From BoldJava:

^ Preheat unit with hopper in to 175C.
^ Pre-measure 230grams
^ Hit E stop and move like the wind
^ Use dual settings.
a. High grown or dense beans: 248C into the first crack plus 45 seconds. Then turn down
to 243C until 2:30 minutes past initial crack of first crack (try to stay out of 2nd crack). I call this a full city roast and is my starting point for working on a new bean. I can shorten/lengthen based on cupping results. Most beans finish between 12:45 and 14:00 minutes.
b. Brazilians, some Indonesians, intermediate elevation beans: 243C/237C, profiled
above
c. Kona and Caribbean beans: 237C/232C , profiled above

I end the roasts with an E stop and cool my beans externally. My current is a steady 120 (variac controlled). My assumption is that you have 220V so trust
that the profiles can be superimposed onto your unit.

From John Despres:

The harder, more dense beans that are typically grown over
5000 feet need a higher initial heat and less at the final stage and the
softer beans, typically grown below 3500 feet should be roasted at a
lower to moderate heat throughout the roast.

I'm guessing your experiment today was a harder bean, maybe a Kenya,
Guatemala or Sumatra. For control are you using the same bean every time?
Also, after preheating to 182C(360F) and the emergency stop, how much does your
temp drop by the time you've reset the GC for the full roast? I find if
I want to start with the drum temp at 149C(300F), I need to preheat all the way
to 250C (482F) and once I've loaded and set the beginning of my roast, I manage
to be at about 149 C (300 degrees F) in the drum.
This is fun.

Enjoying a cup of Yemen Mocha Sana'ani (French press) roasted yesterday
afternoon... I think I'm a bit early and will share my thoughts after
another 24 hours of resting.




In another thread:


Now then, the Gene Café. Keep in mind it's not a typical air roaster, but rather more of a hybrid air and drum roaster. As I understand most air roasters (please correct me here, if need be - my air roaster experience is limited to the Fresh Roast )  beans are heated and lofted by rapidly moving hot air. Aside from momentary contact with the sides and bottom of the roasting chamber, I believe they spend most of the time airborne. The hot air in the Gene Café does not move at nearly the same velocity. The drum, rotating off-axis to the center of the drum not only contains the beans, but also heats them by convection air movement and conductive heat transfer. Meaning the beans are never airborne, but constantly in contact with the outside of the drum and the metal divider plate as well as each other due to the slow rotation of the drum.

I'm a believer in preheating the drum, particularly for more dense (SHG, SHB) beans. I usually preheat to 149C (300F), and by the time I get the beans in and the drum re-loaded, I may lose 12-17C(25-30F). My set temperature varies depending on bean again, but it's usually somewhere between 238-246C(460- 475F). Then, depending on the bean, I'll hit 1st crack about 11:00-12:00. At the onset of first, I drop to 229- 235C (445-455F), flattening out the profile, and I may hit 2nd crack within 5 minutes of the onset of 1st. , if I roast that far.


NB:

turn yellow :165C (330F)
first crack: 204C (400F)