Last night I decided to try a couple of roasts with a modified thermostat stir-crazy. Times and Temps are approximate Ambient Temp:68F Trial#1 : Columbian Popayan Colsuaves (I used what I had left in the bag - I'm guessing just shy of 10 oz.) Preheat to 350F 00:00 to 06:00 : 350F 06:00 to 07:00 : 380F 07:00 to 10:00 : 400F ' 1st crack started at 09:30 10:00 to 12:30 : 420F ' Stopped at just shy of 2nd crack (I think) Ending weight: 8-1/4 oz. Trial#2 : Kenya Eaagads Starting weight: 12 oz. Preheat to 350F 00:00 to 07:00 : 350F 07:00 to 08:00 : 380F 08:00 to 09:00 : 400F 09:00 to 10:00 : 410F ' 1st crack started at 09:55 10:00 to 11:00 : 425F 11:00 to 13:15 : 440F ' Just shy of 2nd crack? Ending weight: 10-1/8 oz. (weight loss just under 16%) I tried the Columbian this morning, it was very good, but I should have roasted another batch with hot-air for a cupping comparison. Compared to what I remember of the hot-air roast, I'd guess this batch had diminished acidity and aroma. It still had a slight fruitiness, good body, good complexity, and was by no means dull. It did lose some of the fireworks however. I'll try it again tomorrow and see if aroma strengthens. I'll try roasting some of the Kenyan Eaagads tonight via hot-air for a comparison cupping this weekend. In terms of Roast Evenness: The Columbian was as good as or better then any air roast. The Kenyan was almost, but not quite as good as most air roasts. I'm curious to see if I can get good roasts with batches exceeding 12 oz. I'm guessing both of these coffees may be better suited to hot-air roasting, but it's always fun to experiment, as one never knows until one tries... In the past, I've had delicious results by blending air-roasts with conduction roasts of the same bean type/origin. John homeroast mailing listhttp://lists.sweetmarias.com/mailman/listinfo/homeroast |
This is very interesting. You are using the $30 popcorn popper, right? How did you measure the temperature? Of the air, or of the bottom plate? (I guress you can't really put any thermometer on the surface because of the stirrer.) Could you raise the temperature more rapidly, preferrably to a slightly higher point? (e.g. 450F) From: "John Wanninger" Subject: +12 oz. w/Stir-Crazy Date: Thu, 17 May 2001 14:57:02 -0500 <Snip> This sounds like the right thing to try. <Snip> My guess is that this is partly because the roast is taking too long time at a lower temperature. I am also thinking about side-by-side comparison of my oven roasting against fluid bed type roasters... Ryuji Suzuki -- Ryuji Suzuki "Slow but steady wins the race." (anonymous, 19c.) homeroast mailing listhttp://lists.sweetmarias.com/mailman/listinfo/homeroast |
<Snip> Yes (actually $6 from thrift store) <Snip> I've got a thermocouple attached to the underside of the heated aluminum "basin" or plate in which the beans rest. The thermostat has been bypassed. I'm using an OMRON temperature controller instead. I'd like to come up with a cheaper thermostat to make the mod cheaper and easier for those who don't have a temperature controller laying around. I wonder if a block with a hole could be attached under the base which might allow a plug-in style adjustable frypan type thermostat/control cord (which I've seen readily available in some stores). As long as you could couple enough heat from the bottom of the plate to the probe of the control, you could probably correlate dial setting to actual plate temperature and have an inexpensive controller (and roaster!). And yes, I could raise the temperature more rapidly. I don't know yet whats the best temperature profile to follow. I guess I'm shooting for an approximate 12min roast time to city/full city. I thought I might try the approach I believe the Alp takes, which is (I think) to slowly bring the beans up to temperature before 1st crack. I've had roasts as short as 9 minutes, and as long as 15 minutes. Lots of experimenting yet to do! John homeroast mailing listhttp://lists.sweetmarias.com/mailman/listinfo/homeroast |
John, I got this url from the alt.coffee group. Thought you might find something here to help in your quest for an affordable controller. I, for one, would be very interested, as I have a stir-crazy sitting in the back room, waiting. When first got it, it seemed to roast pretty well. Now, that I heard it's not hot enough, guess what?...it's not hot enough.:-).http://www.mcshaneinc.com/html/Prod_TempConMostPop.htmlCiao, Angelo | | | > | > This is very interesting. You are using the $30 popcorn popper, right? | | Yes (actually $6 from thrift store) | | > | > How did you measure the temperature? Of the air, or of the bottom | > plate? (I guress you can't really put any thermometer on the surface | > because of the stirrer.) Could you raise the temperature more rapidly, | > preferrably to a slightly higher point? (e.g. 450F) | | I've got a thermocouple attached to the underside of the heated aluminum | "basin" or plate in which the beans rest. The thermostat has been | bypassed. I'm using an OMRON temperature controller instead. I'd like to | come up with a cheaper thermostat to make the mod cheaper and easier for | those who don't have a temperature controller laying around. | | I wonder if a block with a hole could be attached under the base which | might allow a plug-in style adjustable frypan type thermostat/control cord | (which I've seen readily available in some stores). As long as you could | couple enough heat from the bottom of the plate to the probe of the control, | you could probably correlate dial setting to actual plate temperature and | have an inexpensive controller (and roaster!). | | And yes, I could raise the temperature more rapidly. I don't know yet whats | the best temperature profile to follow. I guess I'm shooting for an | approximate 12min roast time to city/full city. I thought I might try the | approach I believe the Alp takes, which is (I think) to slowly bring the | beans up to temperature before 1st crack. | | I've had roasts as short as 9 minutes, and as long as 15 minutes. Lots of | experimenting yet to do! | | | John | | | | homeroast mailing list |http://lists.sweetmarias.com/mailman/listinfo/homeroast">http://lists.sweetmarias.com/mailman/listinfo/homeroasthomeroast mailing listhttp://lists.sweetmarias.com/mailman/listinfo/homeroast |
Thanks for the link Angelo. Looks like they have some neat, reasonably priced controllers. Especially nice are the RS232 models for computer control, at under $200 for a 15A unit, which would easily handle a stir-crazy (or a hot-air unit). This is a great application for a "worthless" old discarded personal computer. For under $100, I see they have a few controllers that would also do the job , although with fewer features and less convenience. For those on a tighter budget, I'd like to come up with a cheap popper conversion, that the average basement/garage tinkerer could do for under $20. That way, even if one bought a new Stir-Crazy, the total cost would stay under $50, which can eases the budget and improves the SAF(spousal acceptance factor). John <Snip> homeroast mailing listhttp://lists.sweetmarias.com/mailman/listinfo/homeroast |