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This is an update on my earlier post on my I-Roast chaff collector
modification. Because I didn't like the very loose fit of the lid assembly
that is on top of the roasting chamber after the modification and even
wondered if perhaps that caused air leakage that was causing the huge
temperature loss I was getting, I undid the modification. (This wasn't as
trivial as I assumed. I had a difficult time getting the nipples to "lock"
back into place.)
Then I tried to think of some other way to lock in the chaff collector ring
and keep chaff from coming up under the bottom and clogging the lid screen.
Eventually I "crafted" an aluminum foil ring of the right thickness which
seemed to do the trick. This was meant as a "proof of concept" solution,
not a permanent one. Then I roasted another batch of Kora beans using Tom's
slow profile. This was too cool after I did the tip sheet modification (see
first post below). With this new modification, I was able to use this low
temperature profile with the same times I used originally.
While I wouldn't put much stock in the results after just one roast, I'm
becoming very suspicious of the tip sheet modification. My testing would
seem to indicate that the reason it lowers temperature is not because of the
tightened chaff collector ring and reduced screen chaff but rather because
of the resulting loose lid assembly seal to the roasting chamber At least,
that appears to be the case with my I-Roast.
-David
Yesterday I made the chaff collector modification described at the end
of SM's tip sheet to my I-Roast. I wasn't having a problem with my roasts
being too dark. (I'm not quite sure what "too dark" means. You can set the
temperature as low as 325 degrees. Are some people getting too dark of a
roast even at 325 degrees?) However, in the hopes that the modification
would result in more consistent results, I gave it a try.
I observe the following changes:
The good:
a.. As promised, the chaff collector is now clamped in and doesn't
rattle.
b.. No chaff that sneaks out. (But then there wasn't much escaping
before the modification either.)
The bad:
a.. The lid doesn't clamp tightly onto the roasting chamber anymore.
Not sure if this is significant or not. This might be a plus for those that
were having problems with the lid being too tight. I suspect this will
become more of a problem with use.
b.. The gasket falls out of the lid now. The gasket nipples don't
hold in the recessed holes. Not a big deal.
c.. The modification makes a huge difference in the display and bean
temperature (as measured by a TC). Before the modification, the display
temp would read about 40 degrees than a set temperature of 350 F and about
80 degrees lower than a set temperature of 450 F. After the modification,
I'm getting about 70 degrees lower than a set temperature of 350 and about
130 degrees lower than a set temperature of 450F. Using Tom's slow roast
profile (2:00 at 340 F, 3:00 at 400F , 6:00 at 450 F) I reached City at a
total of about 8:30 (Kenya Kora, line voltage 117.5 V). After the
modification I barely reached 1st crack at the end of 15:00. I would never
have guessed that what seems like a minor modification would make such a
major difference. Is this difference because the chaff collector is tight
or because the lid is now loose?
Fortunately, the modification is easily reversible.
-David
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