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Topic: update on assorted pumper backtobasics roasting as a forgotten art... (2 msgs / 221 lines)
1) From: fs
I've enjoyed the list contents (arriving via batch mode)and haven't much
time to post. However I'm in need of some advise.
1. I Revived the Back to basics stovetop(BTB) that I had run 70 lbs of
coffee through and had retired due to having wallowed the nonbushing shaft
plate. Minor surgery on the stovetop yesterday with a 3/8" drill and some
1/4 flanged bushings got me running finally. I think Charlie was the one who
observed that I might want to fix rather than buy.... well, once I got there
it cost me the exorbitant some of $2.46 per bushing at Ace hardware with and
with 10 minutes setup and drilling and the gears actually work. Although the
shaft is wallowed by about .050 so I'm thinking now of replacing the lower
shaft. BUT....
 here's the problem. Now I can't get anything but tipped beans... I've lost
my touch. My first batch was to go back to the 620 gram load. Not a good
idea.... plenty of "Grade 7" beans in that load.....
So I dropped to 420gr  EY.. tipped
Tried again 420 gr SM- tipped.
I'm cranking that turkey @ about 80-100 rpm ......
My 620gr profile used to be
deg  time
500 0:00
475 0:10-15
450 0: 20-25
425 0:25-35
400 0:35-45
375 0:55-1:00
350 1:05-1:15
325 1:35-2:00
300 2:15-3:00
325 6:50-7:20
350 7:30-8:20
375 8:20-9:30
400 10:00-11:20
425 11:30- 12:45
Any comments about that profile target above for Sumatran Mandheling or
Ethiopian Yrgachef?
I usually roast dark and pull when engaged in 2nd crack audible. Although
I'm pulling earlier and earlier as I seem to being moving towards liking the
brighter tones of a lighter roast.
What's of interest to me is that I need significant heat during the initial
stages to keep from going below 300 during the first 2:30- 3:00 minutes..
This may be where I'm scorching the beans since my output right now is a
melange of reasonable beans with flyers that are tipped. I have a crabpot
single burner that can kick out 75K btu but I never run it more that the
first 1/8 turn (which is more than adequate...)
Ambient temp on the porch is around 40 F which hasn't really changed that
much.
I have been willing to kick the heat in to avoid the beans dropping below
300, additionally my thermometer (cooper placed in drilled hole in top of
Backtobasic lid) reads low  since it is 435 when leaving 2nd crack.. BTW I
just did a validation of the cooper in boiling water and it's within 5
degrees of 212 so I'm assuming that the 435 reading is due to the fact that
I'm not deep enough into the body of the beans to get an accurate bean temp.
So.
    A. should I worry that much about the sub 300 mark for 2 minutes during
roast?
    B. will 2 minutes sub 300  cause them to be baked?
    C. what size loads do other BTB roasters use and am I overloading it at
430 gr? (pretty comfortable that I'm overloading it at 620)
Due to competing schedules and due to my stubbornness I've been using only
the "pumper" for this last month. So, after a month of  unmodified
popcornpumper coffee even these rough BTB roasts are so much better than my
popper output. The pumper output did achieve a very even roast but at the
cost of flavor. The roasts (100 gr @ a time output) were flat and uninviting
but that might be why people "mod" them as they do to achieve profiling
ability.
Lastly, I'm still plugging away on the 2K drum roaster concept in order to
actually retire both the BTB and the pumper. The Alpha cad files have been
sent to the sheetmetal house for quotes for the drum and I'm hoping for a
prototype system in March. Taking on the learning curve of YACP (yet another
CAD program) has caused me to increase my intake of both  caffiene and
alcohol but I'm encouraged that I have committed to slug through the
"paradigm shifts"  to seeing this version go through alpha phase at least.
But best not overpromise and underdeliver.... suffice to say that I'm
decisively engaged with the project and have high hopes....
If and when I have some time I'll try to post a whitepaper roaster proposal
to all to gather more input about what people would like to see in a 1-2k
roaster.
fred

2) From: Tom Ulmer
Try starting at a solid 400F and put some cast iron under & around it - a
fry pan maybe.
From what I'm gathering from your comments, it seems like uneven heat
distribution is your nemesis.


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