HomeRoast Digest

Topic: Home made drum & roast gone wrong (31 msgs / 898 lines)
1) From: Gary
I'm looking for a little advice. I have been roasting for a couple of years
with Air Poppers, HGDB & SC/TO. I just finished making a drum roaster,
burned it in last night and tried a roast tonight.
I made the drum roaster out of two stainless steel storage cans 6"diameter,
I got at Target, cut the bottoms off at about 2" long, and some perforated
brass sheeting from McMaster Carr.
I roasted a 1/2" batch tonight and the roast came out very uneven. Some
beans were still yellow, some were just into first crack and some were
beyond first crack. I'm wondering what went wrong. Here's the set up:
Grill:	Weber Genesis, Older style with 3 gas tubes, I think 35,000btu or
		The "Flavor grids" are installed but no other heat dissipating devices.
Rotisserie:	Weber, rotates at 3rpm
Drum;		6" Diameter x 12"
		Stainless end caps, each, 1" long
		Perforated brass sheeting 10" long with 4 vanes, 1/2" legs, at 12, 3, 6 &
9 o'clock.
Coffee:	1/2# of Guat San Marcos Finca Maria Elisa
Procedure:	Preheated grill to 500 degrees
		Put cold drum with beans into grill
		Stabilized temp at 475 after about 2 min
		Roasted at 475  and first crack started at 6m 45s into roast
		Turned gas down and heat stayed at 475 to 460
		Thought I heard second crack at 8m50s
		Pulled the roast at 9m30s and dumped into cooling basket.
If I would have let the roast go longer to get all of the beans into at
least first crack, I would have had a bunch of charred ones.
Is the rpm too low or the vanes to short.
I have enough materials to make another drum that would be 4" dia x 6"-8"
long and would like to get the insides right on that one if the vanes are
the problem.
It may be the rotisserie rpm is too low.
The grill held the temperature well and I had lots of heating potential
left. The thermometer is the same one I use in my SC/TO and I find it to be
fairly accurate. Maybe I should stick some fire bricks on the flavor grids
to distribute the heat.
I am trying to get a roasting set up that will allow me to roast 1/2# to 1#
batches. I would probably not need any larger capacity as my wife does not
drink coffee. I'm thinking the one I have built now is way too large for my
Any advice is appreciated.
in Atlanta

2) From: Brett Mason
Do you have vanes inside the drum such that the drums tumble, rather than
just sliding as a mass?
On 6/23/06, Gary  wrote:
Brett Mason

3) From: Brett Mason
...such that the beans tumble.  The symptom sounds as if the beans are not
tumbling (like a clothes dryer)... ?
On 6/23/06, Brett Mason  wrote:
Brett Mason

4) From: Paul Sack
Gary wrote:
You wondered about agitation. Do you hear (or see) the beans moving 
around the drum? You can test this with a cold grill. Your design sounds 
fine, but your vanes *may* be too short.
Oh, now I see the problem. 3 rpm? I think most rotisserie motors are 6 
rpm. I went DIY and built one out of a 50 rpm motor (I think, or was it 
$70?). It's ugly as hell, and one of these days I'll send RK some more 
money and get a real one. But it works. Check Fleabay for a cheap motor.
Taller vanes might solve the problem at 3 rpm. I suspect you'll never 
get a perfectly even roast no matter what you do at 3 rpm, but a mixed 
roast can be nice sometimes.

5) From: Douglas H. Boutell
Gary wrote:
I took out the angle shaped heat diffusor and replaced it with a cookie 
sheet for  more stability with the control of the heat.
I would increase your rpm to at least 25 and which I have used with even 
roast results and when I used a
50 rpm motor it cut my roast time by 1-1.5 minutes for 12 oz of greens. 
in a 5" by 8" drum that my son made.
Try the motor first before you change the vanes.
You might want to reduce the heat so the 1st crack comes  in about 9-11 
min. When I dialed in my BBG
I had similar times for the 1st crack and the flavor was not there 
compared to 9-11 min

6) From: Ed Needham
I think everything is workable except the 3 RPM rotisserie.  You may get a 
bit of heat variation in the 12" and if the beans stay in or near the same 
region in the drum, that could account for some unevenness.  I'd go with a 
faster motor and bet money that the problem will be solved.
I'd also lower the overall heat and extend the roast for that small batch to 
at least 12-14 minutes to second crack.
Ed Needham®
"to absurdity and beyond!"
ed at homeroaster dot com
(include [FRIEND] in subject line to get through my SPAM filters)

7) From: Gary
Thanks Guys,
I'll look for a faster motor tomorrow and then try another batch with
extended times.
in Atlanta

8) From: Ed Needham
Even the faster 6 RPM rotisserie motors are not really enough to get the 
most out of the beans.  Most of us have had the best luck using motors 
ranging from 30 RPM to almost 60.http://www.surpluscenter.com will usually have one that works at a 
reasonable price.  Be sure and call them though, because many of the motors 
available are not listed in the catalog or online.  Tech support people 
there are top notch.
Ed Needham®
"to absurdity and beyond!"
ed at homeroaster dot com
(include [FRIEND] in subject line to get through my SPAM filters)

9) From: Ed Needham
Oh...at SurplusCenter, search on gearmotor AC

10) From: rnkyle
3 rpm motor is the culprit. It is really hard to get and even roast with 3 
rpms. requires extreme patience and heat control. then its hit and miss at 
best, the 5 to 6 rpm work better but the faster motors are the ticket for 
even consistent roasts.
Grill and drum should be level so as not to gather the beans in one area. 
Vanes can be as small as 1/2 to 1" high and still be good to agitate the 
batch size you are talking about. If you want to keep using the 3 rpm motor 
try starting with a lower heat say preheat to 300 and load drum let it come 
back up to 300 and then every min bump it up 50 degrees. With the slower rpm 
motors the drying stage  and pre first require lower heat and more time in 
that stage if you want to get and even roast but it takes trial and error 
and patience with that really slow rpm motor.

11) From:
not seeing your other equipment, this is your basic problem.
Talk to Ron Kyle or go to his website, rkdrums.com
---- Gary  wrote: 

12) From: Ed Needham
I'm not even sure that the level drum is an issue.  Since I've added the 
faster 57RPM motor to my rig, if level, the speed of rotation tosses out as 
much as an ounce or two of beans, since I use an open ended cone instead of 
a latched door on my drum.  I've added a 2x4 under one end of my roaster and 
tilted it to minimize the problem until I figure out a way to slow the motor 
enough to stop the bean spillage.  With my old 30 RPM motor beans tossing 
out was not a problem.  Matter of fact, it never happened.  With the roaster 
tilted quite a bit off level, the evenness of my roasts has not suffered at 
all.  Seems like it should, but it doesn't.
Ed Needham®
"to absurdity and beyond!"
ed at homeroaster dot com
(include [FRIEND] in subject line to get through my SPAM filters)

13) From: Douglas H. Boutell
Either the 25 or 50 rpm works great and the coupling  helps out.http://www.electricmotorwarehouse.com/Dayton/6Z907.htmhttp://www.surpluscenter.com/item.asp?UID 06062412001201&catname=&item=1-1228

14) From: rnkyle
Ed I can see with the open end drum a need for tilting the drum back a bit, 
not a problem with the closed end drum, but with a slower motor, I found 
that getting and even roast was easier with all things level and in line. 
The faster motor is more forgiving and its not a need to be so particular 
with the levelness of the grill. I guess its the toolmaker in me that has 
trained me that all things run better when level and square:O)
This motor for most home roaster will do a great job. It is the one I use 
with the Home rosters combo. Up to 20 lbs a weekhttp://snipurl.com/gmbomodel #3M097
I use this motor for the commercial combo and is more suited for 4 lbs 
batches several times a day or more then 25 lbs a week.http://snipurl.com/h8e1 model #6Z909

15) From: Gary
Ed & RK,
Thanks for the great advice and references.
I will be getting a higher rpm motor and fine tuning the drum roaster.
You guys are terrific to provide this kind of feed back.
Coffee roasting has been one of the most fun things I have ever done. The
support of this list has helped e greatly.
so far I have been able to get two other individuals involved and they love
Also, the breakdown of the $100 trifactor to the resulting cost of a $0.64
for a cup of coffee was very enlightening. Who said this hobby was
in Atlanta

16) From: Ed Needham
57 RPM tosses the beans around pretty aggressively.
I'm pretty particular too when designing things.  The 2x4 is a temporary fix 
until I can slow this motor down a bit.  I'm thinking 45RPM will do just 
fine.  Heck, the old 30 RPM motor did great, but the new 57 RPM motor is 
Ed Needham®
"to absurdity and beyond!"
ed at homeroaster dot com
(include [FRIEND] in subject line to get through my SPAM filters)

17) From: rnkyle
Ed is the person that really inspired me to build my first drum, I don't 
know if Ed was the first person on this list to build a drum, but he is the 
first person that I can remember.
I know when I saw the pictures of his drum and set up I was so impressed 
with the craftsmanship and the concept that I just had to have one of my 
own. Trial and error and several drums, and many lbs of testing and changing 
the design to finally come up with what I have now, the rest is history on 
this end. Thanks Ed for your inspiration and help with drum roasting and the 
concept of gas grill drum roasting. .Truly a pioneer that has inspired many 
on this list and elsewhere. This list never ceases to amaze me, there are 
some really ingenuous members who grace this list, the expert help is 
endless and free.
Tom and Maria have been solely responsible for setting the path for many of 
us on the journey of truly great coffee, and the members of this list has 
helped us all in the journey to the perfect cup.

18) From: Ed Needham
After I built my first drum, I searched the internet and found only one 
reference to a Saeco drum that had flopped and was no longer available.  At 
the time I built mine, it was based on an idea I posted back in 1996, but I 
was so enamored with the idea of building air roasters that it languished in 
the background.  One day I was scrounging around a used restaurant equipment 
warehouse and found a perfed stainless cylinder.  The light went on and I 
bought a bunch of them for $2 apiece.  Went home and built my first drum 
that night and the coffee was so good I never seriously looked back to air 
roasting again.  Here's that first roaster drum... http://www.homeroaster.com/BBQroast.htmlI instantly posted my excitement and design here and on alt.coffee as well 
as my homeroaster.com web site.  The rest is pretty much history.
Roasting sure is fun.
Ron took the idea to new levels.  I had all the intentions in the world to 
make a bunch of drums to sell, but I am not much of a production person. 
Ideas flow like Niagara Falls for me, but grunting out the manufacturing 
just didn't interest me enough to get me off my butt.  Sure, making a little 
extra money was a motivation, but it took someone like Ron to make it 
happen.  The RK Drum has made a lot of homeroasters happy.
Ed Needham®
"to absurdity and beyond!"
ed at homeroaster dot com
(include [FRIEND] in subject line to get through my SPAM filters)

19) From: Scott Marquardt
Have you experimented with any 12 VDC motors? I'm doing a farmer's market
where I'm limited to the car's power, so I hooked up a windshield wiper
motor with a bit of a reduction on it (as well as a DC controller that works
great but may be unnecessary)  Works OK, but I'd like something heavier
I'm not one of your customers, but your work inspired me to do something a
bit outrageous. More on that later.
- Scott
On 6/24/06, rnkyle  wrote:

20) From: rnkyle
This is a multi-part message in MIME format.
Scott I have not tried a DC motor but have a customer in Australia using =
a dc windshield motor, and has posted here on SM list about it and =
supplied pictures of also. A quick search on the archives would give you =
and idea of how Paul did his.

21) From: Scott Marquardt
I had picked one up at a surplus place -- and I've discovered why it was not
in the auto parts stores. The thing heats up quite a bit even under no-load
conditions.  No apparent mechanical problems, though. Bad windings? It
survives even a long roast well, but I find myself waiting for the other
shoe to drop, so to speak. My configuration has flame a bit closer to the
drum than I'm entirely comfortable with (though that hasn't reared its head
in any roasts to date), so a rotation failure would be catastrophic to the
product within seconds, I'm sure.
Which reminds me, I've been wanting to put a safety relay in my popper, to
allow heat only when the fan is on. I can't seem to find Poppery ! units
like a lot of folks, and this is the only good Pumper I have. Bother.
On 6/26/06, rnkyle  wrote:

22) From: Dan Bollinger
This is a multi-part message in MIME format.
Scott, That's because wiper motors are designed for intermittent duty, =
VERY INTERMITTENT!  They are not designed to run continuously.  Dan

23) From: kofi
YMMV: mine has yet to burn out after 2 years use, 100+ roasts, doesn't get
hot either.
I regard 15 minutes use every few days as intermittent.
Wiper motors can run for hours at a time, as they have done for me on many
occasions during  several hundred mile journeys in the rain.
Mr Hadden  down under gave me the idea via this very list some years ago:http://www.haddon.org/Coffee/Roasting/WindscreenWiperRoasting.htmOn 6/26/06, Dan Bollinger  wrote:

24) From: Scott Marquardt
You live in Arizona? Sudan, maybe?     ;-)
On 6/26/06, Dan Bollinger  wrote:

25) From: Scott Marquardt
I like his U-joint extensions, to allow easy removal.
The drum we implemented doesn't need to be removed to charge or drop,
- Scott
On 6/26/06, kofi  wrote:

26) From: David B. Westebbe
This is a multi-part message in MIME format.
Which reminds me, I've been wanting to put a safety relay in my popper, to
allow heat only when the fan is on. I can't seem to find Poppery ! units
like a lot of folks, and this is the only good Pumper I have. Bother. 
That is how I have mine wired up.  When the fan is off, the power is off
totally.  No need for a relay. 

27) From: Michael Dhabolt
Considering the heat capacity of any roaster......I am a FIRM believer
that it should be unplugged when not in use.  So I wire the fan
direct, so that it is always on when the roaster is plugged in.
Simplifies things.
Mike (just plain)

28) From: David B. Westebbe
I agree in principle.  Mine is wired so that the main on/off switch must be
On for the heater to work, and the fan comes on whenever that switch is on.
I also have a thermal fuse which shuts the whole thing down if it blows.

29) From: Paul Sack
I bought a 57 rpm AC motor off E-Bay, and the first time I used it, it 
overheated until a thermostat mounted on it tripped. Usually about 5 
minutes into a roast :) I wired a small fan and set it right in front of 
the motor, and it's run very well, used about twice a week since last 
Scott Marquardt wrote:

30) From: Ed Needham
So a three hour drive through the rain is totally out of the question?  I'd 
think a 20 minute roast would be within it's operating limits.  Overheating 
might be a result of something else.
Ed Needham®
"to absurdity and beyond!"
ed at homeroaster dot com
(include [FRIEND] in subject line to get through my SPAM filters)

31) From: rnkyle
You need to mount your motor at least 6" from the grill and make a heat 
shield that mounts to the grills lid about 1" standoff with a notch to clear 
the spit rod. Some motors have a thermal protections, and if they get to hot 
they shut off. Most gear reduction motors have Delran gears that are pressed 
on the shafts and excessive heat will cause them to turn loose and the motor 
will still run but the gears slip on the shaft which makes them useless, so 
keeping the motor as cools as possible is essential to longevity. Some 
motors are for continuous use and other are for intermittent use, but with a 
fan installed on the back shaft blowing across the motor on ones designed 
for intermittent use, makes them suitable for continuous use. Most home 
roasters are not going to be using the motor for more then 1  to 2 hours and 
with unloading the drum and loading the next batch the motor gets some time 
to cool down. But heat is the destroyer of all electric motors, that is why 
some are thermal protected to shut them down before they self destruct.
So keeping your motor as cool as possible is the key to longevity.
Remember you also have heat transferring thru the spit rod and connectors 
and add that with extreme heat from the grill you have the potential to 
destroy your motor if it is not protected from the heat.

HomeRoast Digest