HomeRoast Digest

Topic: Large batch air roaster (25 msgs / 465 lines)
1) From: Aaron Boothe
Has anyone ever built a large (over 2lbs) air roaster?  If so how big can
these get?  I would like to try and build one (if it is possible or
practical) and I am just wondering if anyone has any experience in this.
Any feedback (related to this topic) would be helpful.
Aaron B

2) From: Aaron Boothe
Actually, even a one or two pound fluid bed roaster would be cool.  And I
mean that as a batch size, not the actual roaster weight...just in case you
were wondering.
Aaron B

3) From: Michael Dhabolt
You'll find a pretty good selection here:http://www.sivetzcoffee.com/online%20catalog.htmMike (just plain)

4) From: True, Dennis W. FC1 (CVN69)
AH Man! why didn't I get there while I was in OR...
FC1(SW/AW) Dennis W. True
"Life Liberty and the pursuit of all who threaten it..."

5) From: Edward Bourgeois
Biggest issue in a fluid bed is heat conservation. For example the
sivetz 1 1/4lb. uses 220v 3.5kw.
On 7/9/07, True, Dennis W. FC1 (CVN69)  wrote:

6) From: Randall Nortman
On Mon, Jul 09, 2007 at 09:21:28AM -0400, Edward Bourgeois wrote:
Yeah, it seems to me that recirculation would make a lot of sense,
both in reducing power requirements and smoke emissions.

7) From: Vicki Smith
Are you hoping to build something you can use for inside roasting? If 
so, you will have a whole lot of smoke to get rid of when roasting 1-2 
pounds of coffee.
Various iterations of the SC/TO can roast between 1/2-1 pound. See: http://biobug.org/coffee/turbo-crazy/for one version of this sort of 
roaster (google for more).
Heat Gun roasting (whether in a dog bowl or a bread machine) can also 
deliver larger quantities of roasted beans and both methods give you 
great control over the roasting process. I use a bread machine, mainly 
because stirring is a problem for me. Both are outdoor sports, well, 
unless you have one heck of a smoke removal system over your stove.
(bread machine FAQhttp://coffeecrone.com/roasting/faq.htm)
Aaron Boothe wrote:

8) From: Edward Bourgeois
Yes recirculation is the way fluid beds are heading with an
afterburner to clean before it is returned. possible but not easy. My
approach has been to mechanically fluidize the beans then add
convection air. The new Lorings sort of do this in a drum where the
drum doesnt rotate but paddles keep the beans airborne.
On 7/9/07, Randall Nortman  wrote:

9) From: David Rolenc
My modified HG/DB will do 1 1/2 lbs. I have a motor underneath that 
stirs the beans and a mount on top that holds the heat gun. It'll do 1 
1/2 lbs (green weight)  in about 20 minutes to full city +.
Aaron Boothe wrote:

10) From: Justin Nevins
David wrote:
My modified HG/DB will do 1 1/2 lbs. I have a motor underneath that
Pictures? this setup interests me.
Justin Nevins
On 7/9/07, David Rolenc  wrote:

11) From: David Rolenc
I'll post some tomorrow.
Justin Nevins wrote:

12) From: Mark Bartkowiak
This is a multi-part message in MIME format.
I agree with David, my HG/BM does a nice job with 1-1/2 lb roast, =
especially with the Milwaukee 8975-6. See Restrictor Plate Roaster on =
www.Homeroasters.org in the contest section.
Mark B. Midland, NC

13) From: DJ Garcia
You'd need a whole lot of hot air to get those beans roasted :-).
Full of hot air in NYC ...

14) From: True, Dennis W. FC1 (CVN69)
I am working on a design now for a Keg/Auger roaster it should have a
15#-20# batch size 
Think Nesco on steroids! 
Not sure if this will qualify as a hot air roaster or mech roaster but
I'm building it.
I'll have pictures once I get done.
FC1(SW/AW) Dennis W. True
"Life Liberty and the pursuit of all who threaten it..."

15) From: Aaron Boothe
Thanks for all of the input.  I am trying to stay away from the HG/BM
though.  This project isn't because I 'need' a bigger roaster or anything, I
just want to make one, simply for the novelty of it.  I am definately
thinking of recirculating air, although I think thats gonna take some
thinking.  Last winter I was in my friends basement and we decided to
recirculate the air (the basement was colder than we were used to roasting
in).  It ended up working better than expected and some Sumatra had to
be...well...'quenched' in a snow bank.  basically the project I have in mind
is simply for the sake of invention.  Thanks for all of the ideas.
Aaron B

16) From: David Rolenc
Pictures are athttp://drolenc.myphotoalbum.com-Dave
Justin Nevins wrote:

17) From: Justin Nevins
Excellent! That's a neat setup. Where did you get the motor? What are the
RPMs (typically)?
For me, I think half of the thrill of homeroasting is making my own
Frankenstein setup. Mine is sort of embarrassing right now, but I someday
hope to build a large-ish fluid bed roaster, so I am always interested when
the topic of home-built roasters comes up. My wife always says that a
homeroaster is part mad scientist.
Justin Nevins
On 7/10/07, David Rolenc  wrote:

18) From: David Rolenc
I picked up the motor at a used electronics place for $40. It is rated 
to do 350 RPM at 24 volts. I typically run it at 6 to 8 v, so it is 
considerably less RPMs than that. I haven't measured the RPMs at the 
voltages I use. I start it out at 8 v and then decrease the voltage when 
the beans lighten up (err darken up ;-) so that the beans don't fly all 
over the place. The stirrer is just a modified aluminum angle I got at 
Home Depot. The steel rod for holding the heat gun was also a Home Depot 
purchase. The sleeve that goes over the vertical steel rod is a section 
of plumbing pipe. The horizonal rod  is attached to the sleeve by MIG 
welder :-P The sleeve/vice grips allows me to position the heat gun end 
exactly where I want. I usually reposition it once during the roast, 
since the beans volume increases. I've been toying with the idea of 
using a stepper motor for that.... Then maybe some PID control to move 
the heat gun.... Boy this is fun :-D
Justin Nevins wrote:

19) From: David Rolenc
Thanks! For cooling, I just pick up the whole thing and dump it (after 
pulling the heat gun and the horizontal bar off completely.) That is 
indeed a non-contact thermometer you see. I measure slightly less than 
180 degrees (angle) from the heat gun position. The vice-grips came into 
play after I melted my set screw bolt when trying to weld it on to the 
sleeve and didn't have another. For now, moving the vice-grips is easy 
enough, although a forked shim would probably work just as well. Thanks 
again for your comments and ideas. I think one of the best things about 
homeroasting is that it can bring out the inventor in all of us.
Robert Yoder wrote:

20) From: John Moody
It is only about twice the power of a P1 popper.  How is that a big issue?

21) From: Randall Nortman
Standard US domestic power outlets are 110V/15A = 1650VA, which is
just enough to run a P1 with a little wiggle room.  To run anything
more powerful you'd need to plug it into an appliance outlet -- 220V,
and those come in different current ratings up to around 40A, but you
don't actually need as much current if you've got twice the voltage.
Most people don't have conveniently located 220V outlets in their
homes, and those that they do have are generally in use by
appliances.  Now, if you're in Europe it's a different picture
On Thu, Jul 12, 2007 at 10:06:40AM -0400, John Moody wrote:

22) From: Rich
NEMA 1-15R and NEMA 1-15P and NEMA 5-15R and NEMA 5-15P are rated at 125V 15Amp.  Those are 
the maximum for current and voltage.  Any lower value of either is within design limits.  Also the max 
VA for this plug / receptacle is 1875 VA wich is also the max watt rating when the load is resistive, 
heating element.
If you connect a device rated at less than 15 amps or 1875 watts and find that you have a definate low 
voltage condition, this is a condition where the voltage at the outlet is lower when the device is 
connected and operating that it is with the device disconnected, then you have a condition that 
should be investigated and corrected.  The a voltage drop in excess of 4 or 5 volts is excessive.
On Thu, 12 Jul 2007 11:11:58 -0400, Randall Nortman wrote:

23) From: Randall Nortman
On Thu, Jul 12, 2007 at 03:18:55PM -0500, Rich wrote:
For a large fluid bed roaster, don't forget the inductive load of a
fairly beefy fan.  Yes, the heater is probably the bulk of the power
usage, but power factor will be something less than 1.  RMS current is
what matters here, not so much watts or VA, because circuit breakers
trip based on current, not power.  (Of course, even on a 15A rated
circuit, the breaker will not trip at 15.1A -- I guess you can
probably push it up to 20A, though you will see greater voltage drop
and you are playing with fire if you try it -- quite possibly

24) From: Rich
The bottom line of this is this:  If you have the knowledge and expertise then there is no real problem.  If 
you do not, then you need to consult with your local electrician to install a dedicated circuit to power 
your coffee roasting equipment.
Failure to do this may possibly result in a fire or worse.
Most of these roasters ae operating at the maximum ratings of a properly installed 15amp circuit.  this 
includes all of the DIY HG/DB systems and supercharged poppers.
In depth knowledge of the appropriate NFPA and NEC sections is recommended.
On Thu, 12 Jul 2007 16:25:01 -0400, Randall Nortman wrote:

25) From: John Moody
This is the kind of talk that makes people think it is a big deal when it is
A 1 to 2 lb spouted bed roaster does not need a fan with a large inductive
Running a dedicated 220V line is a simple matter for someone who owns his or
her own home.  If you don't own, then the landlord would likely not allow
the use of >2000W coffee roasters either, so that's a moot point.

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