edtbjon
Gene Cafe Coffee Roasting Chart
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, 11th October 2014 at 22:37 (7286 Views)
[QUOTE=edtbjon;39971] When I got my Gene Cafe (220V european 50Hz standard), I started out the first couple of batches at max temp (250C all the way) and of course burnt it to black and oily (which was close to my reference from a household oven roasting). This was done well within 15 minutes and the result was barely better than a french roast from the grocery, i.e. dark but really quite thin in taste.
I then found a slow-roast recipe on YouTube which goes like: 180C till 6 minutes (drying phase) then 220C till around 10 minutes (start of first crack territory) and 5-10C increments per minute until done at whatever you like. This approach gave more control and gave me rosting-times around 17-18 minutes. (I was still favouring dark roasts at this point.)
Somewhere around here I found some very useful infomation on SweetM's website about roast degrees with nice pictures on every stage of the roast. Go see and print out for reference...
Then (after a lot of browsing and searching) I decided to go for lighter roasts (read: City+ or so) for e.g. a fruity Panama Geisha or e.g. a good Eteophian Yirgacheffe. I also was inspired and bought a 5kg package ("the fruity package") from a knowledgeable Swedish distributor, to try something new, which I only regret not having found earlier, as there was a lot of excellent tastes to be discovered in these new somewhat lighter roasted beans.
I developed a new scheme: 240C (as the roaster didn't really respond any better at 250C...) up till ending phase of first crack, which is at around 10.30-11 minutes. Then I lower to 225 in order to extend the time between 1 and 2 crack a little bit for control. I rise the temp to 230 at 14 minutes and possibly to 235 at 15-16 minutes (if going for Full City++/Vienna). This gives me very good roasts from City+ (which is as low/light roast as I ever do) to Full City+ and further.
I do have a few (handfull) reference beans in the similar roast degree at hand for comparison. I also use a good light (halogen lamp) which outlights the normal daylight and is invaluable at night, for reference.
In short, my recipe for a good roast of just about any quality bean: 240C till end of first crack (10-11 min), then 225C till 14 min. If not done, rise with 5C every minute until done. Remember that the Gene isn't the best machine for cooling, so brake early. (Good drum machines cool the beans to room temp in e.g. 2 minutes, while the Gene takes 8-10 for the cooling process.)
For whomever is a newcomer to roasting: The roast accelerates throughout the roast (with a a small hint of changing gears at first crack...) so be aware of the speed increase if you are going for at Full City+. Break early, as it will easily coast into a Full French Roast if you wait some 10-20 seconds more.[/QUOTE]