Hello All,

 

I just received my Ambex YM-2 and I am learning to roast on it. I've tried some roasting on it, but I think I am baking my roasts. My coffee smells kinda green when I get done. One example of a roast I perform was:

Ethiopian Yirgy

2lbs

Charge Temp: 285

Time/Degree

1-212

2-233

3-265

4-293

5-318

6-340

7-362

FC@ 7:30 -376

8-383

9-390

10-398

11-416

SC@ 11:36-430

 

Dropped@ 445

 

I had the gas all the way the entire time and had the airflow going inside the drum the entire time. Can someone help me out? Do I need to adjust airflow or burner? A basic sample profile would be helpful too. I need all the help and advice I can get.

 

Thanks!!

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Looks like far from baking your roasts, seems more like going way too fast resulting in uneven undeveloped roast. The YM2 is a 5lb max capacity roaster yet you're running burner full tilt all the way with 2lb charge! First crack at 7:30 on a drum roaster?! Ramping up that fast I'd expect undeveloped grassy taste.

Honestly I don't have time to try and teach someone to roast via Barista Forum. Pay your dues via years of trial and learning or pay your dues going to a roasting school or one on one instruction...
I started to edit my post but time ran out and it wouldn't save, so here goes again after starting dinner. (softening my first post:)

First it sounds like your temp readings are about 20-25f lower than actual, ie 1st crack usually starts more like 395-405f depending on bean and profile compared to your 376f. So I'll give you what I believe is a general "good starter" profile based on your temps for about any bean, a balanced light Full City.

Charge temp depends on load and roaster, also ambient temp, as does applied heat during roast.

6:00min 300f (drying stage) I use full airflow to this point, then drop to 60-80% depending

10:30 370f (browning developement stage) approaching start of 1st, hit the ramp breaks! (I do this both lowering burning and kicking up air flow.)

11:30 380f SOF (start of 1st) final developement stage. I lower airlflow from 100% down to 70-80% after 1st solidly engaged and "over the hump".

15:00 428f EOR (end of roast) just tickling 2nd. About 30sec before anticipated EOR kick airlflow back up to 100%. Heater could be anywhere from 60% to 100% depending on bean and profile.

About any coffee will be quite drinkable that type of profile. Some would sing better lighter, some darker. To find which way you prefer to present the bean roast the same bean same profile multiple roasts changing only the last stage bracketing different EOR temps with same SOF to EOR.

Once you've determined the desired finish temp, next is to fine tune the developement stage ramps...

Regardless the desired finish degree of roast you'll want to keep your SOF to EOR usually at least 3 min and usually not more than 5min, though some profiles some beans targeted for espresso I'll go as much as 6. Important to keep your ramp rate controlled and not stall stretching a finish. You'll need to learn how to control "your" roaster.

Generally speaking shorter SOF to EOR accentuates acidity while longer SOF to EOR sweetness and body.
Actually same can be said for Browning stage, though not so much the sweetness part. Faster for more acidity, slower for more body. But too fast and it can turn out harsh and or grassy, too slow and taste flat. Or so it seems to me based on a scant decade roasting experience.

Drying stage seems to have the least effect on the final outcome. Unless you go too fast and then grassiness can result from there too, though I think I've only experienced this air not drum roasting. But then, I had 6 or so years experience air roast profile roasting before getting my USRC drum roaster...

There are not short cuts. There is no one profile fits all beans. It's easy to turn beans brown, it's a lifetime Journey learning to make each bean sing.
I tried to refrain (but obviously failed) and gotta ask. Why the hell would you want to take a Yirg' even moderately deep into 2nd crack and destroy it's character!
I generally won't go into 2nd crack, but I was trying to make something that is at least drinkable. Nevertheless, I screwed it up too. Right after 1st crack is generally how I like a Yirgy, but with the new roaster I am learning and wanted to see what would happen. Thanks for all your help, you are awesome!!

Mike McGinness said:
I tried to refrain (but obviously failed) and gotta ask. Why the hell would you want to take a Yirg' even moderately deep into 2nd crack and destroy it's character!
BTW, have you availed yourself of the articles under the Information -Related Reading Pulldown Tab on the Ambex website? Lots of great information there. Read everything. Then go back in a week and read again. Then go back in a month and read again. Then go back...

I'll be honest, my frustration and shortness comes from time and time again someone asking questions like you did without first doing their homework. Maybe you did, maybe you didn't I don't know. But think about it especially if you hadn't, doesn't it make more sense to look for information on how to use your Ambex Roaster on the Ambex Roaster (or any roaster related) website rather the "Barista" Exchange website!

I just enjoyed re-reading the "Heat is On" article and gained understandings beyond when I read it last. And gratifying that Terry's description of how to control the roast going through first was pretty much the same as mine above, so guess I'm not totally brained dead yet:)
You are absolutely right Mike. I've been doing homework for a while, but I just haven't been getting the results I was expecting. Its like a rookie who thinks he is ready for the world series the day he puts on his jersey. That's just not so. I've heard from roasters who has been roasting a long time and they are still learning new things. I will get it right soon enough. Your help is greatly appreciated Mike. I owe you a cup.

Mike McGinness said:
BTW, have you availed yourself of the articles under the Information -Related Reading Pulldown Tab on the Ambex website? Lots of great information there. Read everything. Then go back in a week and read again. Then go back in a month and read again. Then go back...

I'll be honest, my frustration and shortness comes from time and time again someone asking questions like you did without first doing their homework. Maybe you did, maybe you didn't I don't know. But think about it especially if you hadn't, doesn't it make more sense to look for information on how to use your Ambex Roaster on the Ambex Roaster (or any roaster related) website rather the "Barista" Exchange website!

I just enjoyed re-reading the "Heat is On" article and gained understandings beyond when I read it last. And gratifying that Terry's description of how to control the roast going through first was pretty much the same as mine above, so guess I'm not totally brained dead yet:)
Paul,
I just sent you a friend request so we can PM each other. I roast on an Ambex YM2 annd 15. I think I can help.

hey paul, how's it going? have you gotten your roast under control? i have a ym2 as well and for the longest time kept getting underdeveloped notes in my coffee. i found this to be related to airflow and drop temp.

at first, i wasn't using a high enough charge temp and was always equalizing at around 150. i found that by dropping at 430 with a charge of 4lb, i was albe raise my equalizing temp to around 180ish (can't remember), but still got some underdeveloped notes.

 

next i tried cutting my airflow back by putting the damper towards the cooling bin. that will split the air 50/50 between the drum and cooling bin. i found that this allowed my coffee to soak up the heat and develop better color wise in the drying out stage.

 

playing around, i just opened the airflow up to remove some chaf and then put it back to the cooler. the results: i picked up sweeter notes and a much nicer body on my shb el salvadoria. it is all trial and error. the best thing to do is to keep a log on your test as every roaster, even if the same, is different. i'm overhauling a samiac and am going to be facing the same thing all over again... 

PS. your roast time is pretty short... that is a pretty fast ramp.

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