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Topic: Help with iRoast 1 - Misty (5 msgs / 187 lines)
1) From: Jay S. Tung
This is a multi-part message in MIME format.
I have been using a iRoast I.  I use the following program..
 
1st stage 335 for 3 minutes
2nd stage 390 for 3 minutes
3rd stage 440 for 6 minutes (but I usually pull it after 4 minutes at =
this
temperature (or earlier).
 
1.	I experience what I believe is 1st crack at the end of the 3rd stage
but it seems to continue well into the 3rd stage with no obvious pause
before the 2nd crack.  
2.	Are my temperature settings all wrong.
3.	Iím not going for French roast or more, more towards city or city =
+,
which is where Sweet Marias tends to suggest.
 
a.	Is it normal for 1st crack to last awhile?
b.	Can someone suggest a profile that is good all around (Iíve tried
many on Sweet Mariaís site but it seems to result in a dark oily roast
before the profile is over.
c.	Can you suggest an exact roast profile for the misty
 
Many thanks!
 
Kamaka
 
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6:50 PM
 

2) From: Ronnie Kramer
I don't think there is one profile that works the same in all IRs.  I use an IR2 and installed a thermocouple last week which has really helped me to understand the roast profile.  Still, you have to look at the beans as they roast.  I have been using the following profile with good results and quick steady rise in bean mass temp;
   
  Stage 1   3:00 @ 350F
  Stage 2   2:00 @ 400F
  Stage 3   1:00 @ 450F
  Stage 4   9:00 @ 420F
   
  The misty valley hits City+ without getting to stage 4, or just as it hits stage 4.  I've stopped the roast right at 9:00 minutes remaing (6:00) into the roast at a nice C+ to C++.  I'm sipping it (2 days rest) right now and it's very nice.  I really love the FC on this as well.
   
  Other beans seem to hit C+ upto a minute or so into stage 4.
   
  If this works for you, you may want to extend Stage 2 for other beans.  On my IR2 it seems that how ever long stage 2 is, 1C starts just as stage 3 is beginning.  And one minute at stage 3 then dropping down gets me through 1C and into 2C.  That is, the bean temp continues to rise in stage 4.
   
  I hope this helps, but my experience is you'll develop your own insight and profile.
  -Ronnie
"Jay S. Tung"  wrote:
                I have been using a iRoast I.  I use the following program..
   
  1st stage 335 for 3 minutes
  2nd stage 390 for 3 minutes
  3rd stage 440 for 6 minutes (but I usually pull it after 4 minutes at this temperature (or earlier).
   
   I experience what I believe is 1st crack at the end of the 3rd stage but it seems to continue well into the 3rd stage with no obvious pause before the 2nd crack.    
   Are my temperature settings all wrong.  
   Iím not going for French roast or more, more towards city or city +, which is where Sweet Marias tends to suggest.
   
   Is it normal for 1st crack to last awhile?  
   Can someone suggest a profile that is good all around (Iíve tried many on Sweet Mariaís site but it seems to result in a dark oily roast before the profile is over.  
   Can you suggest an exact roast profile for the misty
   
  Many thanks!
   
  Kamaka
   
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No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.5.441 / Virus Database: 268.17.36/681 - Release Date: 2/11/2007 6:50 PM

3) From: Vicki Smith
If you are able to go into 1st at, or around six minutes, that may very 
well be as good as it gets. Hearing the cracks is almost always an issue 
with the IR2. Someone recently suggested doing as pan roast of some 
beans so that your ears get more attuned to how roasting beans sound as 
they progress. That may help with your situation. I know that after I 
began roasting in my bread machine, I was able to pick out the sounds 
more effectively when I used my IR2.
My own experience has been that when 1st and 2nd run together, without 
pause, it is generally because I am applying too much heat. YMMV, 
depending on the bean.
The profile you delineate is pretty close to one Tom lists on the site, 
as a good all purpose one. He also lists 4 minutes, on this profile, for 
a city(ish) roast.
 From the IR2 tip sheet 
http://www.sweetmarias.com/hearthware.iRoasttipsheet.html):"A basic profile I am using is my lower-heat warmup profile. It benefits 
all coffees, and only causes problems with really dense seeds that need 
a higher initial temperature. Basically it is
340 for 2 minutes --this will give you a high speed air pattern to aid 
in really even initial heat distribution
390 or 400 for 3 minutes -- this raises the temperature right to the 
verge of first crack
450 for 4 to 6 minutes -- with most coffees, 4 minutes will give you a 
City Roast, 5 a Full City, and 6 gets you to the door of 2nd crack.
I think the best way to use the curves in the i-Roast is to regulate 
initial heat distribution. Air roasters, even the professional Sivetz 
air roasters, have never allowed a slower warm-up "ramp" and this is 
where you can cup quality by letting the coffee accept and distribute 
heat according to its physical limits, not forcing the heat on too 
quickly. Once heat is distributed from the core to the exterior of the 
bean evenly, then a higher roast temperature that allows the coffee to 
pass through the cracks can be applied. If this temperature is not too 
excessive, the cracks will happen in a slow and controlled way, with a 
clearly delineated pause between 1st crack and 2nd crack.
At first I thought I would be using the stages of the i-Roast program to 
regulate the finish of the roast, but realized through trial and error 
(and cupping) that this doesn't make sense. The fantastic thing about 
programming a temperature over a period of time is to get the batch on 
the right "track" for the final finish roast temperature. "
Hope this helps. I can't suggest a good profile for the Misty, sorry. 
 From my POV, the machines are incredibly variable, so suggesting a 
strategy (which Tom does) is ultimately more helpful than providing a 
specific profile. You need to get to know your roaster, get good at 
judging where you really are in terms of roast development, and then use 
the experience you have developed with previous roasts to inform your 
decisions.
Vicki
<Snip>

4) From: Clay Spence
Jay, (Kamaka?)
I had trouble with the Misty Valley too, which is really disappointing given
how much people rave about it, and how much I've liked the Ethiopian
coffees. It seemed to me these beans don't circulate well in the iRoast. My
thermometer showed that the temperature rose more quickly than normal, which
I think is consistent with poor circulation. I haven't had any other beans
behave that way.
Sorry, I didn't come up with a profile that works well. If I try again I
might set the temperatures lower so the fan speed remains higher. If they
really do circulate poorly the temperature may still get high enough. There
was a recent discussion here of iRoast temperature settings and fan speeds,
where someone gave the temperature settings at which the target speeds
change. The iRoast also uses measured temperature to change fan speed, so I
don't know how well it will work.
Good luck,
Clay
On 2/11/07, Jay S. Tung  wrote:
<Snip>

5) From: TINK1969
I have an iRoast 2 and have to remove the screened part of the chaff  
collector and knock the chaff off it a couple of times when roasting the Misty  
Valley.  If I don't the fine bits of chaff clog the screen and the roast  
progresses too fast.  This is the only bean I have to do this with.  
Hope this helps.
 
Kim


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