I've been using a Crazystir/Turbo oven contraption to roast (a blend of beans for espresso) for about 3 years now. Before that I used an air popper. Currently, my roasts are taking about 13 minutes to get to first crack, and about 22 minutes for the beginning of second crack. I'm concerned that this is too slow and I may be baking the beans. I use no profile. My Turbo Oven gets turned on to High (480) and I leave it there the whole time. I'd like to take some steps to taking more control over what is going on and be able to make adjustments. What should my first steps be? purchase a variac? a temp probe? buy a decent roaster (like maybe a Behmor)? switch to single origin roasting to learn more about each bean? I've done lots of reading here on roasting and am a complete novice, despite roasting my own for 5 years. From what I've read here it would seem that i should be hitting first crack sooner; shorter overall roast time; profile a drying time at the beginning; and monitoring both voltage and environment temperature. Am i on the right track here?
Any suggestions from people with more experience would be appreciated.
Thanks,
Barry.

bgn wrote:I've been using a Crazystir/Turbo oven contraption to roast (a blend of beans for espresso) for about 3 years now. Before that I used an air popper. Currently, my roasts are taking about 13 minutes to get to first crack, and about 22 minutes for the beginning of second crack.

Are you preheating the equipment before adding beans? Are the heaters in each half still working properly? How long are the extension cords you're using?

And of course, if it tastes good to the people that matter, don't break a working system.

Barry
Let's start with, What is your batch size? What brand/model are you using for a turbo oven top, what wattage?

I'm using a Sunpentown oven. 1300 watt. I'm roasting about 20 oz (by weight) green. I do not use extension cords. I've never taken the oven apart to inspect the elements, but I suppose they could be affected by oils from the coffee. When I started using this oven (3years ago) I could get second crack by about the 17th minute, now i'm taking up to 24. But I'm not sure the exact cause of this change. I have used different outlets in the house and it could be that the voltage is different. That is why I'm wondering if I need a variac to clear up one variable. I know also that the elements could be wearing out, and so I've considered getting a temp probe to try and measure environment temp and compare it so the oven's LED temp setting.

I'm using the same co on one of my roasters with a 3" spacer, variac and ET/BT thermocouple to a Fluke. My best roast are around 14 oz and are pulled at the first snaps of C2 (16-17 minutes). Sounds like you are trying to roast a few too many beans per batch. Trying 14-16 oz per roast might fix your problem...or the thermostat on your unit may be going bad.

Barry
Sounds like you might have a dirty thermostat and/or some of the connections if your times have increased. Don't think anything is wrong with the element. Agree that dropping your batch size a bit is a good idea too.
This is the basic mod. for converting a top for variac. Done with a Galloping gourmet top TO top conversion

Thanks. I will try a roast with a reduced batch size. I will also pull the screen off of the fan on the oven and see if I can clean up any temp sensor that I can find.

You won't find a probe. Dan could tell you if the thermostat is the same as on a GG top. Or do you have the digital? And how you take apart the next section to get to it. They are generally built well just get a gummy coating. They mostly have the problem of broad temp swings as is the problem with most cheap thermostats used on home roasters and home appliances. I clean and tighten all the heating system contacts every few months including the wall plug. Every watt counts and maintains consistency. Safer too. I've been totally satisfied with TO roasting. Nice way of heat application.

bgn,

farmroast brings up some very good basic questions. Batch size and heating element strength are important data points.

espin wrote:And of course, if it tastes good to the people that matter, don't break a working system

I can appreciate the desire to "make nice", but if the system was working per se, I hazard to guess that bgn wouldn't have posted in the first place.

That said, how does the roast taste? Several threads contain some nuggets of advice with regard to how a long, slow roast will adversely affect flavor. How are you brewing? Have you tried cupping the coffee(s) first to establish a flavor profile?

At the very least, some basic thermometry will go a long way in shining a light in the darkness. If you have visibility into the roasting chamber and some time-keeping device, you can also time color changes, onset of the "wet" smell, onset of the "sour" smell, onset of the "bready/wheaty" smell. These can then be correlated to distinct times within your roast and used as another data point.

-s

I used a similar setup for years (still own it). I agree with reducing he batch size to 14 ounces, but the thermostat conversation has me just a bit baffled because the thermostats on these ovens are awful (not accurate at all, not even close, worthless for temperature control)

My best results from this setup were accomplished bypassing the thermostat completely and using a variac to control the heat and using a temperature probe to measure bean mass temps. If you are uncomfortable removing the thermostat from the circuit, then just run it wide open (full on, max temp)

I generally to get first crack in 9-10 minutes and second crack 3-4 minutes after but I have had some very nice roasts where first crack happened at 11 minutes (still getting C2 3-4 minutes after)