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Topic: IR2 Pocket Thermometer Mod (6 msgs / 158 lines)
1) From: Jim Harrell
This is a multi-part message in MIME format.
First post:
I have been roasting for about two years now and know virtually nothing, =
so
I need some advice. I have an IR2 modified to accept a 550 degree pocket
thermometer. I got both the IR2 and thermometer from SM by the way. I =
needed
a better way to roast consistently. I don't hear well enough to hear all =
the
cracks and I smoke too much to have a great sense of smell. I was trying =
to
pretty much go by sight alone and that was not working as well as I had
hoped.
I enlarged one of the existing holes in the Chaff Collector Lid and =
drilled
right on through the Chaff Filter Mesh. This seems to work great. I have
used this setup for many months now. The thermometer stands straight out =
the
top and extends downward to the very bottom of the roasting chamber. =
Except
for not being able to use the Smoke Vent Attachment, there is no impact =
on
performance of the IR2.
If anyone has also done this type of mod, please comment on degrees of =
roast
obtained while going by the temperature displayed on the pocket =
thermometer
alone. Or, generally, what kind of roast do you think I might have if I
press the button to start the cool down cycle when the thermometer =
indicator
just touches 430 degrees. TIA

2) From: Kit Anderson
Now that you are measuring the bean bed temps, you can use Tom's page as 
a guide. 430F is going to be very light. City at most.http://www.sweetmarias.com/roasting-VisualGuideV2.htmlKit
Jim Harrell wrote:
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3) From: raymanowen
"...what kind of roast do you think I might have if..."
Try a brew and see what you get. The bottom temperature is as good as any to
measure. Just remember, the actual bean temperature in the column will
approach that temperature very slowly. You might try throttling the intake
airflow or add more beans to raise the temperature.
Kit knows what he's talking about!
Cheers -RayO, aka Opa!
Got Grinder?

4) From: David Schooley
My iR2 has a thermocouple inserted into the bean mass. The  
thermocouple is attached to a fast Fluke DMM. 430F to 440F always  
worked well for the City to City+/light Full City range. 425F was  
usually too light for me. I stopped a lot of roasts at 435F. 445F was  
always good for the Full City+ range, and 450F for making sure I was  
into second crack. In other words, Tom's guide works really, really  
well.
Jim,
The profile you are using will affect how fast the temperatures  
climb, which in turn affects how much the thermometer reading lags  
the actual temperature. I am guessing that your thermometer will have  
more lag than my Fluke, but if you keep a log of your final  
temperatures, you will eventually get a handle on what temperatures  
work best.
On Dec 9, 2006, at 8:29 AM, Kit Anderson wrote:
<Snip>

5) From: Jim Harrell
Thanks David. That is exactly what I was looking for. I know about the =
lag,
just don't know how much. I have tried to slow my profile down, while =
trying
not to go too slow. All iR2's are different as we know. I use Stage1: =
325
for 2 min. Stage2: 365 for 3 min. Stage3: 405 for as long as it takes to =
get
to 430-435 degrees on the pocket thermometer. Depending on the outside
ambient air temperature, this takes from approx 8.5 minutes to 10 =
minutes.
As it has gotten much cooler here lately, I may have to adjust my stage
temps. My pocket thermometer has always indicated 350-370 degrees when I
hear vanguard first crack and I hear cracks I believe up until about =
405-415
degrees. After that, my hearing is not very keen. Where do you find =
first
crack with your thermometer David?

6) From: Mike Sieweke
I inserted a thermocouple into my iR1 from below, so it's about
3/4 inch away from the glass and 1/2 inch up from the bottom.
I usually stop my roasts when the beans hit 440F +/- a couple
degrees.
I always program the iR1 for 10 minutes @385F, then 5 minutes @410.
I was getting extremely good results with Java Blawan with
these measured bean temperatures.  They never reached second
crack.
0:00 - 72
1:00 - 261
2:00 - 335
3:00 - 375
4:00 - 394-397
5:00 - 407-408 (first crack starts around here)
6:00 - 420
7:00 - 428
8:00 - 435
8:30 - 437
9:00 - 438-439
9:30 - 439-440 (stop the roast here)
The roast profile depends heavily on ambient temperature and
the amount of fine chaff.  With Kenya AA Mbwinjeru (lots more
chaff) I'm getting to 441 by 9:00, even though the ambient
temperature is cooler.  The Kenya hits second crack just before
9:30, and I stop it around 441/442.
I agree with David.  Keep track of the bean temperatures for
several roasts, and you'll pretty soon get an idea of what
to shoot for.
Mike
On Dec 9, 2006, at 11:10 AM, David Schooley wrote:
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