I tried a little experiment last night with a production roast of a really nice El Salvador. This is my production profile.



My time from 300-330 is 79 seconds: 6:34 - 5:15 = 79. This coffee is very sweet using this profile, but I'd like to find out if I can make it sweeter by increasing yellow phase to 100 seconds.




And this is what I got last night:



Yes, the RoR is pretty ugly. It will take a few roasts to get my heat and air adjustments down. Normally I use 25% air in the beginning and kick it to 50% at DE. But if I'm going to slow the roast to get to 100 seconds between 300 and 330, then I need to do that adjustment earlier and reduced the heat both before and after the air adjustment.

I adjusted it enough to get to 104 seconds by 330*, but then I increased the heat to get the RoR up and left it up too long. I like this coffee between 393 and 395* at drop. This went too far and I had to shut off the gas to even be able to stop it at 398* with reasonable development time. Next time I'll increase the post yellow heat for much less time.

So comparing the taste to my normal roast will not work yet. I'll try it again, maybe with my Cormorant and smaller batches, but I don't use that roaster enough to really know how to control it as well. I'd like to be able to prevent the RoR from rising.

The roast looks great and smells good. It is fully developed, measuring 70/80 Agtron, which is not far off from my usual roast. I brewed a pot this morning and I don't sense any roastiness. There is some acidity, but it's pretty generic. There is also some sweetness. Overall, it is a very acceptable cup of coffee. If I didn't know better, a year ago I would have been very happy with this roast. But it's not as dynamic as the usual roast. While there are no apparent roast defects, there are a few elements missing from this coffee. It might be a touch baked.

The goal for the next roast will be to eliminate that valley in the RoR. I won't mind of the RoR stays level, I don't want it going up. It might not be achievable in a 10 minute roast.

Alan, a couple of questions.

Your roaster has a damper as I recall? Do you have it marked for 25,50 and 75%? Do you think its consistent?

Seems like you soak for 30 seconds? Do you see any interplay with that and the other adjustments you doing, or that's your consistent roast method?

I didn't mark my setting adjustments on this roast. My bad.

My roaster has a 4-position damper. If I switch it to 0, the closed setting, air will actually aggressively blow out of the trier port when doing the cigarette lighter trick! I never use this setting. It will fill the room with smoke.

The second position is what I call 25%. This position actually has a sub-position. When I click the knob to the detent, there is a bit of play in the damper. If I leave it biased towards the 0 setting, then during the ramp, smoke will ooze out of the chimney/hopper. I never use this setting. By moving it 2mm toward the 50% setting, but still in the 25% detent, the smoke gets drawn back into the drum and exhausted out. I'm under the assumption that this position is very close to the neutral/minimum air setting. This is what I call my 25% air setting.

I typically soak for around a minute at the 25% setting. It will change depending on whether it's the first roast or 6th. I can tell from the Artisan BT trace when I need to hit the gas to get the turn on target. If the BT is lagging a bit behind my background template, then I turn on the gas sooner. As long as I'm on schedule by 1/3 the way to dry, I'm happy.

As far as consistency, I can match a background profile, from DE to drop, to 0.6*-1.0* pretty easily. It's easier with constant air. Making mid-roast air adjustments adds a whole other skill level. Like going from playing one piano part with one hand, to playing two parts with both. I'm still figuring it out.

Alan,

Thanks yes that is what I wanted to know. I just moved yesterday to a new air protocol similar to what you are doing and I think I like it. Your explanation of your damper workings is very helpful. I liked how it worked yesterday and will be interested to test it more.

So i went ahead and forget about the ROR and went from this:



to forget about the ROR and paid more attention to timing (extended yellowing and time between cracks):




The last is brazil that was picture perfect but i tried this method on other coffee type but reult was not as good, mybe didnt get it in time.

i on my way to be convinced that all that ROR stuff of sccott is just another myths?
trully, i confused..

Looks like your trying to control your roast with damper settings instead of gas. Try using one damper setting and control your roast with gas.

No...with the gas, the red is the gas the blue is the damper, dumper alway on 5.5