It would appear that each roaster and each bean should be evaluated 
individually.  Obviously some beans just don't look the same at 
allegedly the same roast level.  Many beans can appear to be at 
different roast levels in the same batch.  Immature beans come out 
lighter than mature beans, for example, and dry processed beans are also 
subject to variations in appearance.
I'm not completely sold on using temperature because there can be too 
many variables with that as well.  Commercial roasters are more suitable 
for temperature measurement because of larger batches and longer 
roasting times combined with more uniform placement of temperature 
probes.  Home roasters have accuracy issues with probe placement since 
temperature probes are not often included within the roasting container 
itself due to the methods of agitation required (i.e. turning drums, air 
flow blowers, etc.)  In addition, anyone who cooks knows that you can 
achieve a thoroughly cooked item with either a long, slow low heat 
method (crock pot, simmering) or higher heat (broiling, searing).
So a final roast temperature of, say 450F, might result in the same 
level on a commercial gas-fired roaster day in and day out, but it 
probably has no direct correlation to a FreshRoast, iRoast2, Behmor, 
Gene, Hottop or your backyard grille.
In my limited experience, I rely on a combination of sound, time, 
appearance and relative temperature readings from a fixed probe.  Tom's 
bean chart is my best baseline for comparison until I can find someone 
to really teach me how to do it 'by the numbers.'  In the meantime, I'm 
creating my own pig-trail down the jungle path to coffee nirvana with 
occasional sideways glances in the bushes for snakes.
Homeroast mailing list
Homeroasthttp://www.sweetmariascoffee.com/gallery/main.php?g2_itemIdx20">http://host.sweetmariascoffee.com/mailman/listinfo/homeroast_lists.sweetmariascoffee.comHomeroast community pictures -upload yours!) :http://www.sweetmariascoffee.com/gallery/main.php?g2_itemIdx20

'In the meantime, I'm 
creating my own pig-trail down the jungle path to coffee nirvana with 
occasional sideways glances in the bushes for snakes.'
Great!
Happy Roasting,
robert yoder
<Snip>
Hotmail: Powerful Free email with security by Microsoft.http://clk.atdmt.com/GBL/go/196390710/direct/01/Homeroast mailing list
Homeroasthttp://www.sweetmariascoffee.com/gallery/main.php?g2_itemIdx20">http://host.sweetmariascoffee.com/mailman/listinfo/homeroast_lists.sweetmariascoffee.comHomeroast community pictures -upload yours!) :http://www.sweetmariascoffee.com/gallery/main.php?g2_itemIdx20

I'll respectfully agree to disagree. Many have used bean mass temperature
monitoring quite successfully (i.e. repeatable) for many years on small home
roasting appliances combined with methods of controlling the roaster making
extremely controllable and repeatable and variable profile roasting
possible. Jim Schulman took his Fresh Roast so far as to PID control it via
thermocouple in bean mass. Mike (just plain) did likewise with P1. Actually
Jim went even further and monitored both bean mass and environment temps
feeding the info to the PID in his FR. I stuck with bimetal thermometer bean
mass monitoring with Caffe' Rosto roasting and manual dual variable voltage
control for heat and air flow. Know of some who've added bean mass and real
environment monitoring to their HotTops including going PID roast control
route. My Computer Controlled Hottop (now pretty much used only for sample
roasting and some profile development) has both bean mass and environment TC
monitoring.
Accurately monitoring temperatures does not replace smell, sound and sight
of roast (in that order) but does greatly enhance consistency and
repeatability and predictability.
Now we can add pigs and snakes to augment civets and jacu birds:-)
Slave to the Bean Kona Konnaisseur miKe mcKoffeehttp://www.mckoffee.com/Ultimately the quest for Koffee Nirvana is a solitary path. To know I must">http://www.NorwestCoffee.comURL to Rosto mods, FrankenFormer, some recipes etc:http://www.mckoffee.com/Ultimately the quest for Koffee Nirvana is a solitary path. To know I must
first not know. And in knowing know I know not. Each Personal enlightenment
found exploring the many divergent foot steps of Those who have gone before.
Sweet Maria's List - Searchable Archiveshttp://themeyers.org/HomeRoast/
<Snip>
Homeroast mailing list
Homeroasthttp://www.sweetmariascoffee.com/gallery/main.php?g2_itemIdx20">http://host.sweetmariascoffee.com/mailman/listinfo/homeroast_lists.sweetmariascoffee.comHomeroast community pictures -upload yours!) :http://www.sweetmariascoffee.com/gallery/main.php?g2_itemIdx20

I PID'ed and then did a full PC control of a mod'ed P1 with a TC in the bean
mass. You just have to get the probe to a 'representative' location. Getting
a 'representative ' local is a bit like bear hunting. Sometimes you get the
bear; sometines the bear gets you.
However, it doesn't even really matter if the temp that you are getting is
bean temp, as long as ists repeatable. That way whne you get 425, you can
translate that to what it means toi your roast. Also the thinking was back
then ( don't know if its changed) was that the delta T over time was a
critical factor. I.E bean mass chenging temperature 15 degrees in a minute
based upon bean color / roast stage.
On Tue, Feb 23, 2010 at 4:40 PM, Mike Davis  wrote:
<Snip>
-- 
I've seen things you people wouldn't believe.
Attack ships on fire off the shoulder of Orion.
I watched C-beams glitter in the dark near the Tannhauser gate.
All those moments will be lost in time, like tears in rain.
Homeroast mailing list
Homeroasthttp://www.sweetmariascoffee.com/gallery/main.php?g2_itemIdx20">http://host.sweetmariascoffee.com/mailman/listinfo/homeroast_lists.sweetmariascoffee.comHomeroast community pictures -upload yours!) :http://www.sweetmariascoffee.com/gallery/main.php?g2_itemIdx20

 J.W.Bullfrog wrote:
<Snip>
he
<Snip>
Absolutely Correct!
I ended up building quite a number of (Ubber Popper) clones.  I had an
interest in establishing a consistent reference temperature from one
machine to the next.  This would hopefully allow PID profile (program)
transportability between machines.
The P1 with a tubular glass chimney (the configuration I use) has an
effective roast chamber measuring 3" (three inches) in diameter with a
flat bottom and a initial bean depth (greens) at the start of roast in
excess of 3",  I decided (somewhat arbitrarily) that a Thermocouple
(TC) junction located 1.5 inches from the sides and 1.5 inches from
the bottom would provide me with a fairly uniform bean temperature
measurement location.  I continue to be pretty happy with the
decision. I have been consistent with the TC junction (Omega probe),
TC cabling (Omega wire, flex cables and connectors) and
Indication/Controller (Fuji PXR3) on all but personal and test
machines.  I've found less than 1° F variability between machines.
A number of machines produced as individual projects by some other
folks using somewhat less exacting tools resulted in a bit less
consistent TC probe placement.  This resulted in a bit less
temperature consistency between machines (up to 5° F).  The radial
placement seems to be less important than the vertical placement with
respect to consistency.  Even at this data displacement, poking a
temperature offset of an appropriate amount into the PID brings the
system back to an acceptable ability to utilize profiles (programs)
developed on different machines.
In other words a long pedantic way of saying "Location, Location, ....
Location".
Mike (just plain)
Homeroast mailing list
Homeroasthttp://host.sweetmariascoffee.com/mailman/listinfo/homeroast_lists.sweetmar=iascoffee.com
Homeroast community pictures -upload yours!) :http://www.sweetmariascoffee=.com/gallery/main.php?g2_itemId=7820

On Feb 24, 2010, at 4:54 PM, Michael Dhabolt  
 wrote:
<Snip>
Is the omega probe a flexible probe or did you use a rigid one? It  
seems to ne that a rigid probe would provide the most consistent  
readings.
Which model?
-
allon
Homeroast mailing list
Homeroasthttp://www.sweetmariascoffee.com/gallery/main.php?g2_itemIdx20">http://host.sweetmariascoffee.com/mailman/listinfo/homeroast_lists.sweetmariascoffee.comHomeroast community pictures -upload yours!) :http://www.sweetmariascoffee.com/gallery/main.php?g2_itemIdx20

I just wish there were (was?) a roaster available for purchase with
that type of feature built in.  I can't build it myself without a lot
of time and effort, but I could probably find a way to afford it!
Where by afford it i mean something much less than the sample roasters
from US Roasters and the like - I kinda need something highly
portable, not something plumbed in.  Until the world builds me one,
it's the Behmor (close but no bean mass monitoring) or the RK Drum
(blind luck meets sense of smell roasting) for me!
-F
On Tue, Feb 23, 2010 at 6:53 PM, miKe mcKoffee  wrote:
<Snip>
Homeroast mailing list
Homeroasthttp://www.sweetmariascoffee.com/gallery/main.php?g2_itemIdx20">http://host.sweetmariascoffee.com/mailman/listinfo/homeroast_lists.sweetmariascoffee.comHomeroast community pictures -upload yours!) :http://www.sweetmariascoffee.com/gallery/main.php?g2_itemIdx20

Allon,
Allon Stern wrote:
<Snip>
I use a 1/8" rigid probe.  I can check to see what the Omega #'s are
if you'd like.  If so email me off list.
Mike
Homeroast mailing list
Homeroasthttp://www.sweetmariascoffee.com/gallery/main.php?g2_itemIdx20">http://host.sweetmariascoffee.com/mailman/listinfo/homeroast_lists.sweetmariascoffee.comHomeroast community pictures -upload yours!) :http://www.sweetmariascoffee.com/gallery/main.php?g2_itemIdx20