First Roast. Failure?

[pecanjim]

I just roasted my first pound of beans, Mexican Tabasca '07. I used a turbo oven on a set of nested bowls mounted to a bread machine base to stir. I preheated to 482F, the highest temperature, put in the beans and about four minutes into the roast, a couple of beans popped, about three times as loud as a good coffee first crack. I backed the temperature down to 297F and let it run for ten minutes more. I never got any more pops so I raised the temp to 347 and ran it for another four. Still no pops so I raised it to 401 and ran for another four minutes and still no pops. That was a total of 22 minutes so I went ahead and dumped and cooled the beans. I hand picked a few early nibs and tasted them, they seem to be burnt. My guess is that my first roast is a failure, any ideas where I went wrong.
PecanJim

[Alchemist]

Hey Jim,

Yeah, basically you tried to roast them like coffee. Way too hot. That pop you heard is the equivalent to 2nd in coffee. Basically the signal that you are basically done, if not past (although it is fine for Tabasco). Some beans like the Panama I don't even like to hear a pop.

Next time preheat to 300, put the beans in and let it go a few minutes. I would then lower it to 280 or so. If you don't have pops at 12-15 minutes, and all smells good, go ahead and raise it back to 300-315 to finish.

Slow and easy will win the race with cocoa.

You might have been ok if you had 2-3 lbs in the turbo oven, but with only one pound the beans just rocketed.

[pecanjim]

John,
Thanks. I'll give that a try tomorrow.
jim

[jamescary]

hey pecanjim,
sorry to hear about the beans..
but your roaster setup sounds pretty sweet! i have a turbo oven and am looking to roast in it also.. i was wondering how big is your bread machine? did u need to modify the dough blades?

[Alchemist]

From some of the roasters I have seen used for coffee roasting www.homeroasters.org/php/forum/viewforum.php?forum_id=32 I would suspect it would not be that difficult at all to put together a 5 lb bread machine roaster. The only real concern I see from a BM is that the blades move rather fast and may well break up the beans into nibs. Then again, it might be a good way to just roast nibs.

[jamescary]

I built a Stir Crazy/Turbo Oven roaster based off plans from the coffee roasters; however, I found out it's definitely not ideal without some rather major modifications. I added some simple paddles made out of aluminum foil to the stir arm of the Stir Crazy which allowed it to stir a whole 9 oz of beans (!) (the beans were about 4 deep near the paddles). I did some testing with the Turbo Oven and found that when set to ~300F, the heating element would cut out after reaching ~300F and the fan would proceed to blow out all the heat (I was using a springform pan as a riser). I later found a thread where roasters had said that they split the wire for the heating element and fan and then ran the heating element on a variadic so that the temperature could be more finely controlled.
At this point, I decided that was too much just to be able to roast just over half a pound of beans. However, the stir crazy does provide a nice slow stirring mechanism (altho, it does seem a little underpowered).

[Brad]

James;

It sounds as though you're having fun building new toys!

;D

[jamescary]

Yeah, it's getting out of hand.. Every time we're close to a kitchen store or a hardware store, I've got to go in and see if there's something new that can be used..