Posted Sun Oct 24, 2004, 11:33am Subject: Talking about drum roast profiles and setup...
I'm experimenting with roast profiling on my grill roaster (Alpengrill). Yesterday, I roasted three 1lb batches and decided to play with extending the time just between 1st and 2nd snap. Typically, the time between 1st and 2nd has been about 3 minutes. Yesterday, I extended it 2 minutes by dropping the temp about 2mins into 1st C. I sampled some Kenya (Kenya AA Auction Kiamabara) this morning as espresso and was very pleasantly surprised. Usually, I'm not a big fan of Kenya's as a single bean espresso, but this was very good and had loads of crema too.
Just thought I'd share my roast profile (if you can really call it that) and I'm interested in what variations you folks use. I don't have a fancy digital thermocouple. So, my temp measurements are relative to my TelTru 200-1000F long stem thermometer mounted about 1 3/8" from the lower 1/3 of the drum. The probe tip sits 4" above the burners. The drum sits 2 1/2" above the burners shielded only by a double inverted layer of diamond grill stones.
Batch size 1lb (454gms)
Preheat grill to 650F, open and load the drum.
Temps fall off to about 550F.
~4-5 minutes after load. Watch temp and as it approaches 625F, go to a lower setting that I've got marked.
Temp floats up to about 650 and then drops back into the 600-625F range. I'm also learning to think ahead of the temps a bit since you can't turn grill temps on a dime. There's a lag period, so if I want to avoid climbing above 650F, then I have to think about lowering the flame as the temps are rising through 625F.
~ 9 minutes, temp is moving back toward the 650 range.
Drop to my next lower marked setting, and temp drops back to 600-625F. Until yersterday's experiment, this was my last lowering of the temps from the gas controls.
1st C starts in the 10-13min window depending upon the bean. Monitor temps to stay between 600-625F.
2nd C starts in the 14-16min window depending upon bean (range 600-625F).
My most recent variation is to drop the temp once more (a 3rd time) at 2 mins into 1st C, but not all the way to "low". This lowers the temp to ~ 550F in those last minutes vs the 600-625 range I was using. The thought was to allow the period between 1st and 2nd to be more of a coast than it has been. Some of the info above will shift quite dramatically depending upon the bean variety and whether it's my first or 2nd batch. The 2nd batch will cook quicker and I have to adjust the temps a bit earlier most of the time.
Please share any comments and your particular method/profile,
Posted Sun Oct 24, 2004, 7:49pm Subject: Re: Talking about drum roast profiles and setup...
I'm interested in knowing more about your experiences with the Diedrich. I really don't know anything about a commercial roaster, but have always been interested in how one of them works. Are they basically a huge, gas fired, PID controlled drum roaster?
How would you describe a typical profile with a Diedrich? I've often wondered about the overall roast time, temps along the way, how temperature is managed, etc. Did you follow a variety of profiles for different beans?
Now that I have some very basic control over heat with a grill roaster, I'd really like to take the knowledge up a few notches and see if I could develop some good profiles. So far, I feel that I'm basically managing heat so the roast isn't too slow or fast, and managing time past 1st or 2nd crack. But, it's all that time in between that's got me wondering about the effect upon flavor by varying temps would have across time.
Rick, I've been playing around with different pre heat temperatures and ramping temperatures into first. Lately I have been cutting my temperature to low when I hit First Crack. If I don't hit Second Crack in about three minutes I crank the heat back up to force Second Crack. Once I hit Second I usually cut the heat and coast to finish. my two pound batches running about 17 minutes. I like the long drum profile.
Posted Mon Oct 25, 2004, 2:33pm Subject: Re: Talking about drum roast profiles and setup...
A PID controlled grill-roaster...makes me drool just thinking about it. I saw the thing on the BBQ site you shared. I couldn't tell what it was exactly doing other than including a temp sensor that ties into the main valve.
I did a little net research, trying to glean some info about how a Diedrich is operated. It appears that we're a long way from being able to replicate that level of profiling on a grill-roaster. But it's fun to try isn't it? It may be my imagination, but I've sampled two of the three roasts I did with the longer 1st to 2nd "coast" profile and they are superb. I wish I could actually measure bean temps because I have no idea what they are. Measuring air temp inside the grill is all relative to thermometer probe placement. In my case, I'm measuring temps of 600-650F which is higher than the temps I saw from some of the Diedrich profile info on the net. You might find these two links of interest:
drsmith Senior Member Joined: 8 May 2004 Posts: 178 Location: ny Expertise: I live coffee
Espresso: Mr Coffee Grinder: Crank by hand Vac Pot: n/a Drip: Bunn Roaster: Hearthware prec.; Whirley...
Posted Tue Oct 26, 2004, 8:46am Subject: Re: Talking about drum roast profiles and setup...
My light roast is always done this way - with the long coast at the end. The final temperature isn't high enough to roast the beans any further, but it does drive off some unpleasant flavors. If I stop without doing this, I get that grassy/woody taste that so many of us are familiar with.
My tc placement is a bit different, but my temps are 500 preheat, 400-405 for 9 minutes, 420-425 to rolling first crack, and then drop to low for the remainding 3-5 minutes. Temps in the last leg of the roast drop to 380 or so. I have to bring the temperature back up over 400 to get second crack.
poison Senior Member Joined: 11 Aug 2004 Posts: 1,163 Location: LA Expertise: I live coffee
Espresso: Astra Pro Grinder: Maestro Plus, Super J deal Drip: Cone filter Roaster: RK drum
Posted Wed Oct 27, 2004, 11:59am Subject: Re: Talking about drum roast profiles and setup...
Wow, this was a little over a year ago, and I don't have notes or anything, so lets see what I can tell you.
This Diedrich was an IR12, or Infrared 12. It has a different heating element than a regular gas flame and obviously works more off radiative heat than flame heat.
It was 17 years old or so, and the first and only left hand Diedrich ever made, supposedly. It was 100% manual, with not a digital display to be found anywhere. It was completely analog and manual.
Dick did everything verbally and did not write anything down. It was amazing to watch him roast, or to roast with him around. He could be pulling espressos, and all of a sudden yell instructions across the room, and be 100% right on every time.
The overall roast time varied of course depending on size, of course, but given a maximum load, I'd say average would be 12-13 minutes to first crack at 470-480 degrees (though the problem remained the same, that is not the bean temp), 16-17 minutes to second at 520 or so if you left the temp alone from 1st C on.
What I attempted to do was lower the gas a bit in 1st C, let the temp stabilize and coast through 1st C and on to 2nd, or until about 4 minutes, then turn the gas up all he way to force 2nd around 18 minutes. (If the gas was left alone, the temps would get closer to 550 and go up fast, and it was extremely hard to control, like a runaway train; being the n00b, if I was doing the rare French roast, I could not control it if I let it go.)
That seemed to, as stated above, get rid of any off flavors or grassiness, and give a good chocolatey roast flavor with sweetness.
It is amazing what effects the roast: ambient temps, weather, where the beans are stored (some were inside, some outside in a shipping container: those were cold, and really lowered the roaster starting temps more than normal.)
Dick, as I said, did not write anything down. He definately had different profiles for different beans, and would verbally tell me how each roast should be done, then leave me to it. It was pretty 'seat of the pants'. I wish I had taken notes.
I was really getting into experimenting with the profiles (he didn't seem to mind) when he sold the store and the new owner gave me the boot.
When my grill is up and running, I plan to pick a coffee, say, Guatemala, and roast a half lb, each time trying to adhere to the same profile through 1st, and dump them 15 seconds later each time; then cup each one to see what the differences are.
It is much harder to do in a grill: in a Deidrich, you just pull a sample and keep the roast going, keeping variables to a minimum.
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