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Topic: Drum roaster idea (30 msgs / 648 lines)
1) From: john kangas
<Snip>
I like this idea, I've been thinking about a drum roaster as a winter 
project. Apologies if I've missed any profound thoughts on this, I've been 
offlist for a few months. (I won't let it happen again, I promise! ;-)
I'd been trying to figure it out, supplying heat from the outside of the 
drum. The internal perforated tube should be much more efficient, (thanks 
Ed!) much less pre-drum heat loss.
I'd like to keep it electric, maybe a ceramic element from one of those 
little space heaters...
Any thoughts on proper drum size for 1 lb?
Hmmm, I might have to visit the surplus shop today to check out thier motor 
pile...
John
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2) From: Ed Needham
My BBQ grill roast drum is 5" dia. x 5 5/8" long and perforated.http://www.homeroaster.com/BBQroast.htmlI have only been able to get good roasts to 13oz. so far.  A pound fits
nicely inside, and allows lots of room for agitation, but the roasts come out
flat and uneven when I go over 13oz.  I'm wondering if a larger drum might
allow a pound.  I'm not sure though.
It's a real head scratcher for me, but I haven't experimented with it too
much.  A week of drinking a pound of so-so coffee was a deterrent to more
experimentation, and pounds of coffee (in the name of experimentation) are
hard for me to throw out.
Maybe I'll try a pound again sometime.
Ed Needhamhttp://www.homeroaster.comed
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3) From: jim gundlach
On Saturday, November 16, 2002, at 11:51 AM, Ed Needham wrote:
<Snip>
Just to give another data point.  I made a 6" diameter by 12" long BBQ 
drum roaster that will handle 2 pounds.
Jim Gundlach
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4) From: John Abbott
I could see the use of a 2# roaster only at Christmas time.  Do you use it
often?  I'm thinking now that a 1# roaster would probably be a little
overkill for me. If one were to divide the load and immediately
vacuum/freeze it, I guess it would save a step or two.  I started working on
a drum when you posted your progress last year, but although I had all but
the metal for the body of the drum the project got put on hold.  It will now
stay parked until the first of the year, but I do plan to finish.  I won't
be able to burn wood in mine because I'm using a standard grill.
John - half time - time for a couple of great shots.

5) From: Dan Bollinger
Alternately, heating elements from a toaster oven, but they might be a tad
long, but they sure are easy to find and about the right wattage and
temperature, too. 1# of green beans is about the volume of a 3.5" cube or 42
cubic inches.  I figure a drum should only be 1/5th full for good tumbling
action. That'd make the drum a little over 200 cubic inches or so.  A 6"
diameter drum 8" long would be about right.  Other combinations would work
of course.  Dan
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as
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motor
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6) From: Ken Mary
<Snip>
Industrial kilns use a maximum volumetric fill factor of 15%. Using this
factor, your drum should roast about 1/2 pound. But this factor is mainly
due to the proper working of the flights to avoid segregation and heating
only the outside of a "rolling" bed. Also, the most efficient length to
diameter ratio is between 4 and 10. Extrapolating this to our "toys" is
difficult, but the correct size should not be that far from what I described
above. I have no idea how coffee roasters are sized.
--
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7) From: James Gundlach
On Saturday, November 16, 2002, at 12:45 PM, John Abbott wrote:
<Snip>
I have five coffee drinkers in the household.  We are moving to taking 
three thermoses full to work.  Two pounds don't last a week.
Jim Gundlach
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8) From: john kangas
Okay, so about 6" diameter by 8 or 10" sounds like a good ballpark starting 
point. I've got some 2" stainless thinwall tube sitting around, that might 
work for an interior heat supply thingy.
Now for aeration- I can track down perforated stainless, and ventilate 
through the drum itself. Or- Some of the drum roasters I've seen pull air 
from the upper end with a centrifugal type fan. This might be easier, 6" 
solid stainless is easy to find. (truck exhaust, unused of course!) If I 
used a pusher type fan, then keeping the whole thing airtight wouldn't be 
such an issue. A little unheated air leaking into the drum could be a real 
problem with only 1500 watts to work with.
Well, off to the surplus shops!
John
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9) From: Ed Needham
The Frontgate waste can drum is 8" dia. and 13" long.  I plan on using it (I
bought the pair before they took them off their product line) on my next drum
roaster project.
I guess the problems I had with roasting a pound in my BBQ grill roaster are
related more to roast profile than drum size.
6" x 12" seems like it would be an ideal size for a homeroaster setup.  Do
you have pics or a previously posted description of how you built it?
Ed Needhamhttp://www.homeroaster.comed
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10) From: AlChemist John
Sometime around 08:57 11/16/02, john kangas typed:
<Snip>
I was thinking of buying and wrapping my own nichrome coils.  The raw wire 
seems quite inexpensive
<Snip>
I have my eye on an electric ice cream maker motor.  The one I found about 
60 rpm, 1.5 amps with good load capacity (has to stir stiffening ice cream).
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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11) From: Jim Karavias
Hi John,
I thought you might like to look at this.  It is full of info about heater
elements.  Perhaps overkill for a coffee roaster but interesting.http://www.euclids.com/element-design.htmRegards,
Jim Karavias

12) From: jim gundlach
On Sunday, November 17, 2002, at 08:01 PM, Jim Karavias wrote:
<Snip>
A very interesting and informative site.  Sites like this and 
SweetMaria's are what makes the web worthwhile.
Jim Gundlach
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13) From: Dan Bollinger
We have a Euclid kiln at work!  I have one of their tee-shirts with their
yellow sun logo on it.  :)  Their kilns have a programmable controller with
saved profiles, btw.  Dan
<Snip>
cream).
<Snip>
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14) From: Dan Bollinger
<Snip>
There are companies that will custom coild heater elements.  You tell them
the voltage, amperage and temperature and they'll engineer one for you. Not
expensive.
<Snip>
cream).
Good idea.  Those little synchronous gear motors are very quiet, too. You
can find them in Graingers, too.  Dan
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15) From: AlChemist John
Sometime around 06:01 11/18/02, Dan Bollinger typed:
<Snip>
I will check out Euclid's.  Whereas the FAQ on heater coils was good, it 
seems the rest of the site basically said "contact us for more infor.."
<Snip>
I'll check when I get to work today.
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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16) From: Dan Bollinger
I believe AMACO in Indianapolis will make custom elements.  www.amaco.com
Dan

17) From: dewardh
Dan:
<Snip>
Wouldn't it be easier to just go down to the nearest Home Depot or wherever and 
buy whatever combination of 300 and 500 watt quartz bulbs gives the power you 
want?  They're $5.00 each at this place:http://www.elights.com/quartzlamps.htmland not much more at the Depot.  Ceramic sockets are only a little harder to 
find . . . worst comes to worst you could dismantle a couple of work lights . . 
.. (I got a dual housing/dual bulb 1600 watt total thing on a tripod *new* at 
CostCo a year or two ago for about $50 . . . there's your heater(s), sockets, 
reflectors etc. already mounted and ready to go . . . put 'em on the variac and 
dial in whatever wattage you want).
Deward
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18) From: Dan Bollinger
I believe one or two roasters use halogen bulbs as the heat source, but
don't quote me!  One problem with them is that the envelope is very tender
when hot. Any jarring (drum rotation?), rapid temp changes (cooling fan
turns on or chaff hits the bulb?) will destroy them in a flash.  One roaster
I know of that uses them (I think) is the Pro1500.  From what I can tell, it
uses the very hot envelope temperature to act as a afterburner to clean the
exhaust without venting.  Dunno how they accomplish that. Dan
<Snip>
wherever and
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you
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to
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lights . .
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at
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sockets,
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variac and
<Snip>
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19) From: AlChemist John
Sometime around 13:24 11/18/02, dewardh typed:
<Snip>
A little bulky for the design I have going.
<Snip>
No variac here, too pricey.  Looking at higher design stage and less on the 
fly adjusting .  Rather just design the watts I need.
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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20) From: dewardh
Dan:
<Snip>
don't quote me!  One problem with them is that the envelope is very tender
when hot. Any jarring (drum rotation?), rapid temp changes (cooling fan
turns on or chaff hits the bulb?) will destroy them in a flash.  One roaster
I know of that uses them (I think) is the Pro1500.
Yes, no, and yes  . . . the PRO 1500 uses, if not exactly "standard" 
quartz-halogen bulbs, something very similar.  There does not seem to be any 
"problem" with "ruggedness" (and even if there were they're cheap and easy to 
replace).  But in fact the bulbs are quite sturdy when "derated" by a few 
hundred degrees (and glowing orange instead of bright white).  A 500 watt 
(rated at 120V) bulb dissipates about 325 watts at 100V, and is not likely to 
present a "mechanical" problem in a roaster.  Use four of them . . . 1300 watts 
.. . . should be plenty . . .
<Snip>
uses the very hot envelope temperature to act as a afterburner to clean the
exhaust without venting.  Dunno how they accomplish that.
The PRO 1500's "heaters" are in the roast chamber, and don't seem to have 
anything to do with the "afterburner" (which seems to be somewhere in the 
exhaust stack).  I didn't notice any of the telltale "flashes" or "puffs" that 
one sees when chaff hits the heating element in an Alpenrost, either, so the 
PRO 1500's chaff filter seems to be effective in keeping chaff away from the 
heaters . . . that may be a good part of the reason for less smoke.
I'll offer too, for your consideration, that if chaff (and beans) are kept away 
from direct contact with (or over-close exposure to) the heater then "smoke" is 
a sign of *severe* over roasting (or "charring"). Even with a bright light 
shining directly across the exhaust I seldom see *any* smoke when roasting 1/3 
lb. batches to "full city" with a Cafe Rosto . . . I'll say again what I said 
before . . . all that smoke from an Alpenrost is just evidence of bad design . 
.. . specifically the (lack of a) chaff collector and poor heater element 
placement.
Deward
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21) From: dewardh
John:
<Snip>
If you want to "profile" the roast, or compensate for different bean 
requirements, or different ambient, or different roast size or, or, or . . . 
you have to be able to adjust heat input.  There is no one "watts [you] need" . 
.. . (unless you just go for "too much" and modulate heat input some other way, 
like adjusting airflow).
Deward
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22) From: AlChemist John
Sometime around 23:14 11/18/02, dewardh typed:
<Snip>
Considering this is definitely a hybrid, yes the design has other airflow 
control by either fan speed control or air flow direction, have not decided 
which yet.   Similarly, I plan of wiring the heater(S) onto a series of 
switches to help control heat input.
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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23) From: AlChemist John
Sometime around 09:51 11/16/02, Ed Needham typed:
<Snip>
I looked at your drum roaster on your site.  Very nice.  What is the specs 
of the rotisorre (amps, rpm, etc ) and since it was new, does it list a 
maximum load to rotate?
Could it be you need more heat input for a pound? (not that 13 oz isn't a 
lot more than the 100g I am doing now)
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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24) From: AlChemist John
Sometime around 09:51 11/16/02, Ed Needham typed:
<Snip>
Could you tell before tasting that is was only going to be so-so?  If so, 
maybe try using $0.50/lb Viet Robusta just for test/throw away sake.  I 
think that will be my plan.
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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25) From: Ed Needham
The rotisserie motor is out in the detached garage right now, and I'm too
lazy to go out and get it to look up all the specs.  It's just a typical
'Char Broil' brand rotisserie.  Nothing fancy at all.  I think it cost me $30
at Home Depot.  It's geared really slow, and could probably turn any amount
of weight I put on it.  Those things are designed for cooking whole chickens
or large roasts.  It plugs into standard house current, and shows no
indication of stress when roasting a pound.  I'm going to put the Frontgate
waste can on the rotisserie and see if I can do two or three pounds at a
time.  I don't think the motor would strain even with that load.
As to the heat per pound, the BBQ grill itself has quite a bit of reserve
heat.  I usually roast just above a low setting, with the thermometer reading
500F to 525F (I know that sounds high, but it's probably a false high
reading...the roasts, at 13oz. come out great.  If I cranked the heat up all
the way, it would probably quickly hit 700 or 800 degrees.  When roasting at
night, and preheating the grill, I have seen the lower grid get red hot.
It's funny though, when the wind is blowing hard, the grill temps can quickly
change.  I have to keep a close eye on the thermometer.
I've got quite a greens stash building up, and there may be a couple of
origins that I wouldn't miss too badly if I messed up a pound or two.  I need
to roast tomorrow, so I'll give it a try again at a pound, and report back.
Ed Needhamhttp://www.homeroaster.comed
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26) From: AlChemist John
Sometime around 18:55 11/19/02, Ed Needham typed:
<Snip>
That helps somewhat.  Can you estimate the rpm's?  Is it in the 4-6 
category, or 60-100 rpm?  Likewise, could alp and HT owners estimate the 
drum rotation speed the machines use?  Thanks.  I want to try an get in the 
right ball park.
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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27) From: Ed Needham
Probably 20-30RPM.  The beans are constantly tumbling, and there is really
not much time for them to scorch as they tumble.  It's not nearly as fast as
a commercial drum roaster, but it is fast enough.  I 'think' the Alp and
Hottop have a much faster rotation.  I have not used either one, but I saw a
Hottop video which showed it spinning fairly fast compared to mine.
Ed Needhamhttp://www.homeroaster.comed
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28) From: AlChemist John
Sometime around 20:55 11/20/02, Ed Needham typed:
<Snip>
Thanks Ed.  I have  a 20 rpm motor I was looking at. That seemed about right.
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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29) From: Dan Bollinger
<Snip>
right.
Three seconds to make a revolution? Sounds just perfect to me.  Dan
<Snip>
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30) From: Bart Frazee
I timed my HT yesterday at 57 rpm. 
Bart
On Thu, 21 Nov 2002 08:52:47 -0500, you wrote:
<Snip>
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