Well I finally got around to trying out the SC/TO yesterday. Roasted up the UGH!! beans from Tom. I had only a few slight issues that I would like to bring up. - The beans never reached second crack. It seemed that I couldn't get it hot enough. My turbo oven goes up to 480F, which should be high enough. I also have the heating element turned off on the stir crazy. Could it be that I'm roasting in my garage where it was only 38F at the time? Is ambient air influential like it is with a popper? At 22 minutes the beans were at a city or city+ roast. - Chaff removal wasn't as good as I'd like. I have the aluminum strip bent open for an outlet, but the slow rotation didn't rip off the chaff like it does in a popper. I figure that I'll have to go back to the colinder/fan for cooling and chaff removal. Thoughts? Greg
Greg.... ambient air does have an effect. You may want to build a cardboard wall around the unit, sorta box it in. Three sides with a top will help. The aluminum in a permanent bend to let the chaff out is letting heat escape too. You could bend it back shut, but prop it open only during times when lots of chaff is flying. If you're somewhat skilled you could put a switch on the SC element; just be sure to use one rated for 10 or more amps. Being able to add bottom heat when desired helps. Hope that helps, peter <Snip> unsvbscribes) go tohttp://sweetmarias.com/maillistinfo.html#personalsettings
Greg, My TO goes to 500, but otherwise I have the same setup as you do. My first dozen roasts were with both the SC and TO as heat sources, and the results were quick but good. I had to turn down the TO to extend roast time past 10 minutes. When my shaft broke and I redid it, I also disconnected the SC heat element. Now my roasts take 15-20 minutes and seem more uneven. The unit also needs the chaff slot temporarily plugged to gain heat early on. Solution (being persued by a couple of us): Put a switch on the SC element and use it as a booster to preheat or to alter the roast profile along the way. I'm thinking that the circuit for the thermostat might be a good place to put a switch, but the one thing I can't remember -- is the thermostat open for "off" and closed for "on" or vice versa? Or does it matter? Tom in GA
Hi Greg, You are correct. Ambient temperature does affect roasting. Are you reading the temp by the dial or do you have a thermometer or TC? Not sure what kind of TO you have, but it has been my experience that the dial is grossly inaccurate. On two of the TO's I have tried I had to modify the dial so it could be twisted past the stop in order to get to second crack. Now I monitor temp with a thermocouple so I get a better idea of what is going on. Another idea would be to bypass the thermostat altogether and put it on a switch, at least 15A. I bet you could cool the beans with a hair dryer set on cool, and that would blow away the chaff. Works for me anyway. Just need to be careful not to blow the beans away also. Hope this helps, PeterZ About to go outside and roast coffee in 85F weather, here in LHC. Greg C. Rose wrote: <Snip>
Thanks for all the help with my learning curve on the SC/TO. I didn't realize that the temperature control on the TO is inaccurate, although now I am not surprised...I have some mods I'm going to try to get to second crack. First, I'm going to install a thermometer in the roaster. I wonder how accurate that would be? I'm afraid that the thermometer is going to measure the air temp while the beans are a different temp. Secondly, I'm going to put the entire apparatus in a box like I do with my P1. Hopefully its the ambient air temp that is killing it. (Glad that summer is almost here) Third, I'm closing up the bent aluminum piece for chaff removal until things really get going. Finally, I plan on wiring a switch for the heating element on the SC as a booster. I will do that only if the box doesn't help it out. Thanks for all the great insight and ideas! Greg Roasting in a P1 while the SC/TO is in the shop...
Try to locate the thermal probe at the level of your bean mass, best you can... Brett On 4/4/06, Greg C. Rose wrote: <Snip> w <Snip> y <Snip> -- Regards, Brett Mason HomeRoast ...who wants to sell his Silvia and pursue an espresso machine upgrade..= .
Just to jump on this thread, i just got my mod parts back from my brother i= n law, he is a metal fabricator. I had him create the ring and make the paddles sturdier for me, nice thing was it is all fabricated out of stainless except for the cap over the nut which is copper, he said it wont even affect the roast. I'll post pics later, but the cool thing is he fabricated four flanges (???) to hold the lid on properly so i wont have to worry about the lid coming loose during the roast. I roasted my first batch durting my lunch break, i roasted a pound of the Sumatra WP Decaf for my father in law. raoseted using a temp curve someone posted earlier modified for my own use 300 deg for 3 minutes 390 till first crack, started around 9 minutes 450 after first crack till the end of the roast at 18 minutes a bit into th= e second crack where i like it for decaf. Looks great, a rather dark roast, which is normal for a decaf at that point= , darker than a non decaf would be, the experience was great, its fun to watch the roast change and smell the smells, the roast was pretty even, and the roaster was much quiter than i expected which will be rally nice in the summer, i can roast after the kids are asleep and not worry about making too much noise on the porch. Cant wait to get home and roast a pound of regular i think i have a pound o= f Gethwumbini thats begging to be roasted On 4/4/06, Brett Mason wrote: <Snip> ttings <Snip> -- "Good night, and Good Coffee"
I would spring for a thermocouple meter that can handle two probes. On mine I mounted the first thermocouple where the thermostat for the stir-crazy is (someone has posted a picture of this on a website). The second thermocouple is in the air above the beans. The difference between the two readings is a good indication of roast velocity. On 4/4/06, Greg C. Rose wrote: <Snip> w <Snip> y <Snip>
on my SC/TO, the chaff is swirled about not by the slowly turning SC arm, but by a fan in the TO. On a working SC/TO, this is pretty obvious, since the SC arm rotates clockwise (usually), and the TO fan spins counter clockwise (always) I'm assume that any turbo oven would work the same way because this is a pretty basic design requirement. You have to have some mechanism in the TO top to convect the air in the oven, ie, if the oven is gonna convect, you have to have a fan. All convection ovens have them (conventional ovens may or may not?). anyway, if the fan is missing (or not working), then the chaff won't get blow around, and it's likely that the oven won't heat the way it's supposed to. I have pictures of this sitting on my camera waiting to be posted as soon a= s my card reader unlooses itself (or I buy a new one) --mike On 4/3/06, Peter Zulkowski wrote: <Snip> p <Snip> . <Snip>
Buying a replacement is the surest and most certain way to make a missing object come out of hiding. My experience, anway. Bill On 4/5/06, Michael Stock wrote: <Snip> n <Snip>
Bill, I will have to remember that as "Morgan's Corollary to Murphy's Law". Brian On 4/5/06, Bill Morgan wrote: <Snip>
well, it's still missing, but I scrounged around, and pulled a cable out of some crack somewhere that i was able to get to work in a very crippled way. it's mighty annoying and time consuming, so i won't be pulling off a whole bunch of pics. anyway, pic of the fan is posted at www.bubbles.boldlygoingnowhere.org/coffee if my server is working like it's supposed to, which is about 5% of the time. --mike On 4/5/06, Brian Kamnetz wrote: <Snip>