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10/15/2021 2:19 AM
merlot85, maycondelpiero and hoeltz, Welcome !

10/14/2021 10:06 AM
Thanks for the addition to the group. Seriously considering building a drum roaster along the lines of oldgrumpus's. Love the design and craftsmanship.

10/14/2021 4:00 AM
Morning, ar3mia ! and... coffee drink

10/12/2021 11:55 AM
Evan Slack and CupOfJoe, Welcome !

10/07/2021 3:24 AM
Larry140, Roastiva and fkrauthan, Welcome !

In Memory Of Ginny

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RK Mobile Mod
Hoomin Bean
In case I forget to mention this on every post, this is one of the most
useful forums I've ever seen on the internet, populated by some of
the most inventive and helpful folks I've had the pleasure to lurk around.
Well, my lurking days are over, so here goes:

Had my first espresso in Italy in 1973. Spent most of my
working life in construction and facility maintenance. Now 56,
in 2005 I bought a Seattle Coffee Truck and started a business
with my oldest son (32) vending at music festivals, etc. I've purchased a RK Drum and a BBQ
grill to roast onsite at festivals and at least one farmer's market that
I am already associated with as a beverage concession.

Besides documenting my progress on the roaster build, I hope this
thread will contribute to our shared info base for
Health Dept, Agriculture Department, etc regulatory experience
as well as what needs to be brought to the design process for mobile
roasting. Now, those of you who may already be selling at farmer's
markets are probably roasting at home, and bringing your product,
since farm markets are
usually only a few hours long. I intend to
transport everything to my events because when
I head out into the mountains for a blues festival or whatever,
there may be 2-3000 people milling around, camping, eating, and
even shopping for 3 days and a couple nights. We're already used to
loading and unloading our tent, tables, granita machine and more,
so another piece of equipment to lug around does not dismay us.

I'll upload pics as I work on the assembly, but to start, I'm attaching
a jpeg snagged off the web of the grill I bought, Charbroil Commercial Series,
chosen partly because it is all stainless, a material that delights Health Inspectors.
I realize that roasted coffee is not the "finished" food, as it is recooked by the
consumer, and therefore does not face the same scrutiny as a latte or a burrito,
but these are the guys that come to my booth anyway, and when you create
an overall impression of competence and professionalism, inspections go very well.

I will happily share anything about my experience in this field, because,
far from wanting to protect a proprietary business know-how, I would love
a lot of people to get into this kind of thing, so that the general public can
start to expect quality coffee at their favorite festivals and events. It can
only benefit all of us. Just don't show up at my shows! Grin

The grill has a side burner, which will be useful to boil water for americanos,
and for cupping batches. It is 50k btu, possibly an excess capacity, but I've
noticed from the posts the the faster and hotter you can roast, the sharper
and less baked the product is. By the way, we currently get killer espresso from
a Philadelphia roaster (our region) and for now we are only going to try to master
a drip roast.

Finally, special thanks to Tim Eggers, who gave me some observations
and advice via email, while I was thinking about this.
Edited by ginny on 05/27/2008 3:56 PM
Nice post, Hoomin Beans:2s:2s:2

I have a VERY similar grill... for grilling food! I'm not positive, but you may want to add some flashing to the back opening of the lid. Preheating for cooking burgers and steaks, I notice the temp on the grill stalling out around 450F (on the built-in thermometer). Tons of heat rolls out the back of the lid. I found this out when I smelled toasted cedar durning my first grilling session - ended up being the deck railing! This grill was in the exact same place as my previous one, the difference is all the heat that rolls out the back.

Keep us up to date on your progress! Excellent insight!


Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
Kaffee Bitte
Welcome to drum roasting. I will be very interested to see how you solve the problems of electricity to spin the drum. This is the only thing holding me back from roasting at the market I sell at. I had thought about fabricating a pulley system that I attacked to a foot pedal allowing me to stand next to the grill and spin, but I usually have to much to focus on just selling.

On another note, once you have some practice with the roaster you really should try working up some espresso blends. They really are not as difficult to get right as you might think!

"Some days it's spice, other days it's bitter dirt."
Some of the fellas in one of my other interests (Ceramic Grill smokers) use a DC (car) battery with an inverter to run electric devices where AC isn't available. I don't know how long it would power our roaster motors, but is just a thought. There's also a small gas-powered generator which would not be uncommon around a campsite.

Bring it on there Hoomin and welcome aboard!

Hoomin Bean
Thanks for your replies. I've got pics for later today when I sit back down re: the first assembly quandry and its solution, but I'll respond to the electrical stuff.

When I am with my coffee truck, which will be most of the time since I'm be roasting at weekend shows as the main thing, and one Wednesday market for sure, I have a 50 amp generator on board, muffled exhaust, and though I'm running a several hot items - drip coffee, espresso machine, granita machine, refrigeration, and hot water tank for hand wash sink I can juggle my load. Occasionally we've had to leave the espresso machine off while making several airpots of coffee, but often the facility can provide a single 20 amp circuit, which means I can run everything. We do 3 urban festivals in Harrisburg where we can just list our needs and they give us unlimited amperage from subpanels spaced regularly in their Riverfront Park. Yep, the park is wired for parties! At those affairs, we've run all the above plus a convection oven for fresh baked cookies, and never turned our generator on.

The single farmers market I'll be at (for now) is an organic, local producers market located at a historic grain mill and they have power available.

When I started this business, I was a little overwrought about how to run a energy intensive concesssion in situations where there was limited or no local power. As it turned out, the generator has never been a problem, because when they are allowed, everybody else has a louder one, when they are not there is usually power available. And if no power and no generators allowed, well, no Hobo Ed's Espresso either! Draw a 100 mile circle around your hometown and you will find so many things going on you won't know how to choose between them. Anyway, the point of mentioning my early anxiety is that I did a ton of work on small scale solar and wind until the math forced me to understand that just to supply the high cycling element in the espresso machine I would end up with a trailer full of batteries for the amp hours demanded, which could not be reasonably recharged in a typical Pennsylvania environment between the Saturday of the show and the Sunday. Or, even if they could, it would require one bank of batteries charging while the other worked.

But in fact, the roasting operation solo stands the chance of being supported by a reasonable solar array to recharge a battery or two with inverter as Rick mentions. Speculating from an armchair without looking anything up, I'll presume that the cooling will require more amphours than the drum motor. We do a couple zero-waste energy fest events where the generator is mildly problematic, but not so much that everyone won't ignore it because they want their coffee! Solar roasting at any kind of alt-fest should be a definate door opener for the vendor committee!

If you haven't seen this one, check out this guy's solar roasters:

Helios 1

Helios 2

Kaffee Bitte
Coffeenut. I have read a decent amount about those two solar roasters and they both seem to take a good long time to get the coffee up to the temps that are needed. As I understand it they also require a great deal of sun. From the companies site material it sounds like they recommend only using them in places with mostly sunny and warm days (almost sounded like they were hinting at desert conditions only). Seems to me that much of the East coast would have a hard time getting these to work on a regular basis.

I know a small batch roaster using similar methods out in Seattle who had bought one of the Solars and sent it back post haste. I honestly don't know why she thought Seattle of all places would find it useable. She started out using the bbq grill. Now though I think she has worked up to a 10 pound air roaster, with plans to upgrade to a 25 pounder soon.

Seems to me that the solar power array to power the energy requirements of the motor and cooling mechanism would be more functional and require less sunlight.

"Some days it's spice, other days it's bitter dirt."
Hoomin Bean
That solar roaster is wild. Thanks for providing the link. The array I was thinking about previously had to do with flexible solar panels, which I figured I could stretch across my tent, to charge a battery or two.

Oops, a PM from Ginny made me realize I haven't been signing my name, though I've referred to my eponymous biz.

Hoomin Bean
So, I ordered the universal rotisserie that is linked to here and there, and found that on my grill I had quite a long span to cross, resulting on one end in a handle that barely grasped the rod and on the other in a motor forced to be less the the furthest possible distance from the heat.
Hoomin Bean attached the following image:
short rod[648].jpg
Hoomin Bean
I went to my local welder, who shook his head sadly, as I wanted to stay all stainless. A series of phone referrals and a one hour drive got me to a stainless-only dealer who didn't mind selling 4' of rod. The rod now goes all the way up the handle, and on the other side the motor is mounted at the far end of the side shelf. By the way, that shelf is 2 pieces of (curled? bent? braked? uhh....) steel screwed together, and the resulting unit screwed to the sidewall of the grill, which is pretty much a sheet metal box. It was kind of wobbly. I used JB Weld copiously, joining the two parts, and then joining them to the sidewall. It's pretty stiff now, and fine for mounting a motor.
Edited by Hoomin Bean on 01/13/2008 7:03 AM
Hoomin Bean
However, this result bugged me a little. There was quite a bit of flex in the rod with the drum empty and the rotation was clunky. By this time I had bought the universal rotisserie, discarded the motor, discarded the meat prongs, discarded the spit, and had spent my money on 2 metal clips, their accessory screws, and a wooden handle. s:6
Hoomin Bean attached the following image:
long rod long span[650].jpg
Hoomin Bean
Well, I have another pic of what I did next, basically set the clips inside the grill to reduce the span, but my laptop crashed, can't find the operating system, may loose the photoshopped next pic, but that is the least of this morning's bummer. Logged onto my wife's laptop to explain. See ya when able. :(

Kaffee Bitte
Hoomin Bean! Something that might help with the "clunkyness" of the spit rod, is to get a counter weight. I have been experimenting with this lately with somewhat decent results, though at loads about 2.5 pounds the benefits are negligable. Below this weight though it takes away any annoying clunking sounds.

I'll have to repost later with a link to it since I have to go deliver some coffee right now.

"Some days it's spice, other days it's bitter dirt."
Hoomin Bean
re: shortening the span of the 5/16" rod, on the handle side it is easy to imagine flipping the mount to the interior, but on the other side the rod bears on the lovejoy connector to the motor. I wanted to use the clip that came with the rotisserie for mounting the little 6 rpm motor. Obviously, I was going to need a bearing, preferably stainless, which felt a little discouraging - it is an odd need, a round bearing with collars or some kind of rim, and a set screw for grasping a square rod. I mean, I didn't want to buy another rotisserie!

Looking at the meat prongs closer, I realized that the prongs were 2 pieces of round rod pinched into a groove on a stainless steel bearing. You can see by the picture how the prongless bearing will fit.

I might be obsessing on this, but by 'clunky rotation' I meant a sort of bounce, that I was pretty sure would be a sag with a loaded drum and a hardship on the motor. Maybe it is not an issue.

Lynn, I am very interested in finding out what you meant by counterweights. I don't really understand, but I assume that is me. :|
Hoomin Bean attached the following image:
roaster, rh clip[661].jpg
Hoomin Bean
The groove being pinched to hold the prongs means of course that the groove is distressed on its outer?...upper? edge, needing some clean up. This post is only to show off this cute little grinder. We've spent quite a few years together.
Hoomin Bean attached the following image:
santa fe, roaster 038[662].jpg
Kaffee Bitte
The counter weights I was speaking of are similar to the one in this link.

I started experimenting with them because my drum with loads under 2.5 lbs makes this horrible clunking sound. I was concerned it would stress the motor. the counter weights sort of help, though not as much as I was hoping. I think I will still use them, but with seedlings help I am working on a different approach to shore up the rotisserie rod itself.
Edited by David on 05/27/2008 11:26 PM

"Some days it's spice, other days it's bitter dirt."
Hoomin Bean
I installed a 3/16" plate across the back to cover the vents and to provide a little more temperature stability and recovery, I hoped. It weighed about 16 pounds on the bathroom scale. Pre-roast, and with temperature probe installed, I played with the gas valves and discovered I had a unit with a fast temperature gain that mostly had to run on the lowest couple settings except while preheating. There are 4 burners, so only 2 are directly under the drum. Immediately I wanted to fiddle with all four on their own terms, so I started playing with raising the end ones higher so I could keep the flames down under the drum, as I'd heard of scorching issues here on the forum too. I also caught on that when you got to temp, just flapping the lid up and down an inch or two was another way to control the roast. What a blast! Fiddlin the knobs, flappin the lid...

After the first burn-off with a half pound of beans, I roasted 3 two-pound batches over a few days. All of them were very even in color and degree of roast. One was too light, pulled by mistake; one was dark and rich, very popular here at home; and I liked the 3rd batch best - same bean, Costa Rican, full city+. I didn't legitimately log these, but I'm using a guideline of: preheat to 535-540, install drum fast, recover to 525 within 3-4 minutes, hold there, first crack at 12 minutes, lower temp to 505 or so, then to taste. Recovery was really no problem on a 38 degree day, and stability was better that I had hoped for.
Hoomin Bean attached the following image:
Kaffee Bitte
The plate across the back will help tremendously in keeping more heat in the roaster. Mine has worked wonders.

Is your drum a solid sheet or is it perf sheet? I can't quite tell from your pics. If it is solid I wouldn't worry about scorching due to the direct flame too much. It can be a big issue on my perf drum, but I have found that my 57 rpm motor keeps most of this problem in check. Another thing you might want to think about if your drum is solid sheet, is a temp probe that is actually in the drum. Fred (sdcoffeeroaster) has a nice one setup. Check out the Snowy Coffee Roasting thread to see it.

My grill also really pumps out the heat. In the summer I have to have ceramic bricks under the drum to moderate some of the heat.

Work on your heat dumping methods, because you are going to need them when the heat of summer kicks in. I actually use some extra ceramic bricks to prop the lid open by varying degrees. It gives me a good deal more control over the ambient temps with my high powered monster.

"Some days it's spice, other days it's bitter dirt."
Hoomin Bean
It's perforated, Lynn. Great tips on summer roasting, thanks.
Um... who told Lynn about summer? Isn't that still legend up there?

Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
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