I've been roasting on a Diedrich IR-7N for the past couple of weeks and am having trouble creating a good profile....I've been roasting an Ethiopian Kaffa Forest from Atlas Coffee Importers in Seattle. 

I'm roasting at about 5,300 feet elevation in dry colorado air.

Started off following manufacturers recommendations....Here's a breakdown of my 1st couple 5lb roasts

#1 

Gas on WC meter: 2

Charge Temp: 422

Drop Temp: 225 (forgot to log)

Air 50/50 280degrees: 2:27mins

1st crack (switch to roasting thru Drum):  390  (forgot to write time as I knew it happened way too quick!)

Roast finished: 425 in 7 minutes!!  

#2

Gas on WC meter: 1.25

Charge Temp: 402

Drop Temp: 203 @ 1:20mins

Air 50/50 280degrees: 3:50mins

1st crack (switch to roasting thru Drum):  385 @ 9:40mins

RAMPED UP gas to 1.5 @ 12:40 mins since it wasn't climbing

Roast finished: 422 in at 16:09 which is an insanely long roast development stage. 

#3

Gas on WC meter: 1.5

Charge Temp: 418

Drop Temp: 213 @ 1:20min

Air 50/50 280degrees: 3:12mins

1st crack (switch to roasting thru Drum):  390 @ 7:25

Roast finished: 423 @ 10:25mins  

#4

Gas on WC meter: 1.4ish

Charge Temp: 420

Drop Temp: 211 @ 1:27min

Air 50/50 280degrees: 3:20mins

1st crack (switch to roasting thru Drum):  390 @ 7:43 

Roast finished: 422 @ 11:00mins

#5

Gas on WC meter: 1.4ish

Charge Temp: 383 (was trying to slow roast down, this way....good idea??)

Drop Temp: 209 @ 1:18min

Air 50/50 280degrees: 3:13mins

GAS LOWERED to 1.25 @ 3:33mins

1st crack (switch to roasting thru Drum):  383 @ 10:45mins

ROASTING seem to stall at 383 so I brought gas up to 1.5 @ 11:15mins then 3 @ 12mins and then to full bore which is a 6 @ 12:30mins

 

Roast finished: 423 @ 15:25mins

#6

 Gas on WC meter: 1.4ish

Charge Temp: 377 (was trying to slow roast down, this way....good idea??)

Drop Temp: 195 @ 1:30min

Air 50/50 280degrees: 4:07mins

1st crack (LEFT AIRFLOW AT 50/50 to try for a steady climb???):  383 @ 9:35mins 

Roast finished: 422 @ 13:10mins

I'm having a hard time finding out the ideal way to create my initial profile.....seemed to get the steadiest temp climb leaving it at 50/50 from 280degrees on?? What sort of effect does this have on the beans?? 

Based on my numbers, what variable should I try changing 1st?  At what roast stages should I be increasing the gas or decreasing?? From my very little experience, it doesn't seem like I'm gonna be to keep the gas steady throughout the roast??

Thanks in advance for any suggestions!  I'm gonna be roasting again on Saturday and would love to have some new things to try!

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I have been roasting on an ir7 for 8 years. Here are some things that i find work well for me.
-optimal batch size is 12#
-charge temp usually 400-410
-bottom out temp between 160-175 @ 1:30
-50/50 @ 270 degrees
-1st crack at around 385-395
-3-5 min bean developement time
These are general guidelines that i found were important when i first started out on ir7. They are not absolutes just solid guides until you get comfortable with this roaster.

Let me know if this helps.
Good luck
nick
Thanks Nick!!
Where do u have the gas set at various stages of the roast??
Have u tried a 5lb roast in the ir-7 with any success? Not at the point yet where I can unload 12lbs frequently enough to experiment a

The temperaure really depends on where the roast is heading based on the specific coffee I am roasting. Temperature is dictated by several factors, but for you it will be very different than for me due to the different batch sizes we are roasting. Obviously a smaller batrch like what you are currently roasting would require less heat than the batch sizes I am roasting so it really would not translate well for you to follow my temperatures. Some factors that will determine this would be:

-the specific coffee being roasted

-the roast level you are looking for

-the bean developement time you are looking for as well as total roast time

-flavors you are looking to discover with the given coffees being roasted

as well as many other factors. It really is something that takes time to figure out and develope over time. Its time and experience that will help you figure out your "roasting style" which is why it is truly an art form. The guidelines I gave you earlier were just to give you initial direction when there is none at the early stages of learning to roast. There really is no book to teach this, but those were some important benchmarks that I came across as I look back to my early roasting days. They will help you with producing some better roasts but they really need to be flexible each time you load up your drum. Had someone pointed those things out to me early on I probably would not have blown through nearly 500lbs of coffee which was undrinkable. lol.

Keep me posted.

Nick

Are you not using 100% airflow at anytime? Typically, around 240 or first color turn, you'll need to blow off the chaff. And again, around 370 you want to blow of smoke and reduce the air pressure in the drum by moving to 100%. I also think it would help to find one constant and make changes from there, such as using the same drop temp each time, etc.

David, I agree!  Need to get better at only chaning one variable.....need to start blowing of the chaff as I haven't tried that and it should slow down my climb to 280!

Roasted 6lbs of greens yesterday, here's the breakdown:
Gas on WC meter: 1.4ish
Charge Temp: 374
Drop Temp: 201 @ 1:20min
(Decreased gas down to 1.0 @ 2:40 as temp was climbing too fast)

Air 50/50 280degrees: 3:40mins
(Increased gas back to 1.4 @ 6:10mins as the climb slowed)
(Increased gas to 4.0 at 370degrees @ 8:40mins knowing that when I switch to roasting through the drum shortly it will struggle to steadily climb to finish temp)

1st crack: 384 @ 9:48mins
(Decreased gas to 3.0 @ 10:20 as temps were climbing pretty fast and I didn't want to have an insanely short roast development stage)

Roast finished: 423 @ 13:00mins

Cupping tomorrow, but I assume its similar to my past efforts.

For my next roast, I would like to go in with solid #'s to try. 1st of all I'm having trouble getting the drop/bottom-out temps down to around 160-175degrees....to hit those numbers I think I'd have to start with a charge temp of 350 or maybe even lower. Any negatives that could come up from starting that low? Had a hard time in my 1st couple roasts going that low, but think its the 1st thing to get under control! Also curious about whether I should try to steady the temps around 350 by teasing the gas or airflow beforing dropping the beans into the drum? Scared with the beast having so much thermal mass and how quick it can go from 350 up to 370 with no beans in the drum.

Also, any suggestions for probes/software I can use to chart the roast temps on my laptop?


Thanks again for the suggestions.....I look forward to hearing people's thoughts as I continue to experiment!

Well guys, I've been really busy with my day job so I've only been able to roast about a couple of times since my last post.

Would love if someone could look over my roast logs and point me in the right direction.  After reading Diedrich's roasting manual I think I'm getting to the 280 degree temp/yellowing stage where its recommended to switch the air to 50/50 way too quickly even with the gas really low.....from your guide I should be 6-7 minutes into the roast but I'm repeatedly getting there at around 4 minutes....wondering what effect this has?  

These 1st 3 roasts, I forgot to blow the chaff off but remembered on my most recent roast last weekend....I feel I have the gas pretty damn low but perhaps I need to start it at .75 or so on the WC meter?

1. Six lbs. Ethiopia Sidamo

 

Gas at start of Roast on WC Meter: 1.0

Charge Temp: 358 degrees ("through cooling bin")

Drop Temp: 193 degrees at 1:17min

280 degrees to 50/50 position: 4:00min

 

(Gas upped to 1.4 WC at 320 degrees 5:45min)

(Gas upped to 2.5 WC at 350 degrees 7:30min)

 

1st Crack 382 degrees at 9:20 min (switched to "through roasting drum")

Finished at 418 degrees at 11:45 min

 

 

 

2.  Six lbs. Ethiopia Sidamo

 

Gas at start of Roast on WC Meter: 1.0

Charge Temp: 356 degrees ("through cooling bin")

Drop Temp: 185 degrees at 1:20min

280 degrees to 50/50 position: 4:45min

 

(Gas upped to 1.4 WC at 320 degrees 6:50min)

(Gas upped to 2.1 WC at 348 degrees 8:50min)

 

1st Crack 383 degrees at 11:05 min (switched to "through roasting drum")

 

(Gas decreased to 1.5 WC at 390 degrees 11:30min)

 

Finished at 416 degrees at 14:15 min

 

 

3. Six lbs. Blend (50% Brazil, 25% Guatemala, 25% Ethiopian)

 

Gas at start of Roast on WC Meter: 1.4

Charge Temp: 360 degrees ("through cooling bin")

Drop Temp: 197 degrees at 1:20min

 

(Gas decreased to 1.0 WC at 252 degrees 3:00min)

 

280 degrees to 50/50 position: 3:45min

 

(Gas upped to 1.4 WC at 350 degrees 8:15min)

 

1st Crack 384 degrees at 11:30 min (switched to "through roasting drum")

 

(Gas increased to 3.0 WC at 370 degrees 10:18min)

(Gas increased to 4.0 WC at 398 degrees 13:00min)

 

Finished at 432 degrees at 15:30 min

Last weekends roast:

Six lbs. Blend (50% Brazil, 25% Guatemala, 25% Ethiopian)
Gas at start of Roast on WC Meter: 1.9
Charge Temp: 379 degrees (Airflow Vertical "through cooling bin")
Bottom out temp: 194 degrees at 1:27min
Chaff Removal: 245 degrees at 3:00min (Airflow to Horizontal "through roasting drum" for 60 seconds then back to vertical)
(Gas decreased to 1.4 WC at 3:50min as I thought I was getting to the yellow stage too quickly)
280 degrees to 50/50 position: 4:00min
1st Crack 391 degrees at 9:55 min (Airflow to Horizontal "through roasting drum")
(Gas upped to 2.0 WC at 10:55min)
 
Finished at 435 degrees at 13:40 min
 
Any pointers on how to improve from here would be greatly appreciated! Really dumbfounded as to what I'm doing wrong?  Is the gas too high?  Should I be dropping the beans at a higher temp like 390?  Really frustrating repeatedly getting dull/flat coffee! 

I'm new to this forum, but I've been roasting on 2.5 and 12 Kilo Diedrichs for awhile and have logged about 1500 roasts on them (not to mention many hundreds more on my Quest). That said, I still have SO much to learn and am always looking for a way to get better.


Just a thought, but no need to give a partial batch any gas for the first minute or minute and a half. there's a lot of heat in that drum.

Also, I found that the temperature targets you see and read about concerning the IR roasters need to be "calibrated" for your situation (and batch size). Try some roasts, taking note, specifically of the yellow temperature. Then try going to 50/50 a bit before yellow (maybe 1 minute). Also, look at 1c and go to RD about 20 degrees before. This will change by roaster, batch and by bean but you'll get the hang of it. On a small batch on the 2.5, I might hit 50/50 at 250, but on a larger batch on the 12 it might be closer to 290 or 300.

Also, I've found that 270 is a little early for 50/50. I am typically about 290 or 300. I've heard that altitude is a big factor too...

Can't wait to dig in deeper on this forum!!

Jed - thanks for your participation.  We're just purchasing an existing roastery and acquiring a 10 year old (although in primo shape) IR7 and could use some tips.  the current owner pretty much uses the same profile for all his coffees"

charge variable drop from 300-400 depending on batch size

TP @ 1:30; air @ 20%

270 @ 5:00; switch air @ 50/50

370 @ 10:30; switch air to 80%

Drop according to roast level.

what I'm experiencing in difficulty ramping into 1C rather than the slow straight-line RoR for 10 lb. batches.  Would you say this is indicative of an IR-7?  don't have enough experience yet to find what the sweet spot is...maybe 50% capacity?

Looking at the burners through the sight glass they're all glowing brightly so maybe it's the nature of the beast!

Thanks

Dave


Jed Vander Zanden said:

I'm new to this forum, but I've been roasting on 2.5 and 12 Kilo Diedrichs for awhile and have logged about 1500 roasts on them (not to mention many hundreds more on my Quest). That said, I still have SO much to learn and am always looking for a way to get better.


Just a thought, but no need to give a partial batch any gas for the first minute or minute and a half. there's a lot of heat in that drum.

Also, I found that the temperature targets you see and read about concerning the IR roasters need to be "calibrated" for your situation (and batch size). Try some roasts, taking note, specifically of the yellow temperature. Then try going to 50/50 a bit before yellow (maybe 1 minute). Also, look at 1c and go to RD about 20 degrees before. This will change by roaster, batch and by bean but you'll get the hang of it. On a small batch on the 2.5, I might hit 50/50 at 250, but on a larger batch on the 12 it might be closer to 290 or 300.

Also, I've found that 270 is a little early for 50/50. I am typically about 290 or 300. I've heard that altitude is a big factor too...

Can't wait to dig in deeper on this forum!!

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