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Hybrid DrumAir Convection
John Despres
The goals:

I want to roast up to 2 pounds.

I want to keep it electric since I understand it.

I want to roast indoors. I'm not fond of the idea of dragging gear, beans and so on to the great outdoors. I also live in Michigan where winter can be tough.

I want a cyclone chaff collector.

Here's what I have so far:

Two 7 1/2 quart colanders. Here's one.
John Despres attached the following image:
Colander[1096].jpg

Edited by John Despres on 10/08/2008 9:52 AM
Respect the bean.
John Despres
Fresh Roast 8, Gene Cafe, JYTT 1k, Quest M3, Mazzer Mini, Technivorm, various size presses and many more brewers.
John Despres
The idea will be to stack the colanders together to make the drum giving me a 15 quart capacity drum. I plan on using rivets, screws and clips in order to modify - no welding.
John Despres attached the following image:
Colanders stacked[1097].jpg

Respect the bean.
John Despres
Fresh Roast 8, Gene Cafe, JYTT 1k, Quest M3, Mazzer Mini, Technivorm, various size presses and many more brewers.
John Despres
Here's a colander with 2 pounds of monsooned malabar in it. It looks like there'll be plenty of room for 2 pounds of smaller beans.
John Despres attached the following image:
Colander with beans[1098].jpg

Respect the bean.
John Despres
Fresh Roast 8, Gene Cafe, JYTT 1k, Quest M3, Mazzer Mini, Technivorm, various size presses and many more brewers.
John Despres
Thanks to Brian, I chose a folding vegetable strainer to use as vanes.
John Despres attached the following image:
Petal strainer[1099].jpg

Respect the bean.
John Despres
Fresh Roast 8, Gene Cafe, JYTT 1k, Quest M3, Mazzer Mini, Technivorm, various size presses and many more brewers.
John Despres
That's all the pictures I have for the moment.

I think with proper vane design, using the curved portion of the drum will give me plenty of tumble for 2 pounds of beans. Out from the center, up the ends a bit and back to the center, and repeat. Maybe...

I may drill out the extant holes to a slightly larger diameter. At the moment, I don't plan on adding holes and letting the solid portion of the drum act as a conductive source as well as the hot air. If I get scorching and tipping, I can always add holes.

Making the drum rotate will be easy,; I just need to find the motor. It seems consensus says something around 60 RPM will do the job, so that's what I'll look for.

Heating the beans - Will a good heat gun do the job, or will I be under powered for two pounds? If I am under powered, perhaps I could add another gun from a separate circuit and use two. This seems like the easiest approach to me at the moment if heat guns might work. I could always find oven heating elements and use them. I suppose I'd need to wire a 220 circuit for it. Perhaps I could use both a gun and a heating element...

I plan on supporting the drum with roller bearings inside the housing.

I can cut out the bottom of one colander to add & remove the beans.

I'm considering making the drum tip in order to remove the beans. That's mechanical and will be pretty easy to design.

I plan to use sheet aluminum to build the housing and will insulate the entire thing so I can rest my forearm on it while it's at full heat. There's been much discussion of insulation here, so I'll refer to those posts.

I also plan for a cool air intake to help regulate drum temperature. I think this needs to be at the bottom so cool air can be drawn upward.

I'll also have a chimney to vent smoke outdoors.

The part I don't understand at all is how a chaff cyclone works. I've looked at the Sivetz air rosters but I can't figure it out.

And I'd like a temperature probe in the beans.

If anyone has any thoughts, I'd love to hear them since most of you are, well, geniuses when it comes to this stuff. Me, I'm just messing around.

I'll begin drawings and will add them as I go along.
Edited by John Despres on 10/08/2008 11:01 AM
Respect the bean.
John Despres
Fresh Roast 8, Gene Cafe, JYTT 1k, Quest M3, Mazzer Mini, Technivorm, various size presses and many more brewers.
seedlings
Go John! I'm watching and waiting anxiously!

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

probably more than you ever wanted to know, but this is the best cyclone design info site I've seen.

http://billpentz....yclone.cfm

I will watch your project with interest.

Brian
bvwelch
Looks like a very cool project.

I look forward to your success, and want to learn how to do 2 pounds also.

I don't know if this is helpful, but for some reason my projects seem to find a sweet-spot at 1.5 lbs.

With 1.5 lbs, I can use a turbo oven and a big steel bowl, or a stock pot with the heat gun, or even a good-sized bread machine loaf pan with a heat gun. All of them give pretty good results.

But with 2 pounds, in a bread machine, or using a turbo-oven, the roasts stretch out to 20 to 25 mins. Perhaps OK, but for myself, I'm happier at 1.5 pounds.

-bill

seedlings
You *can* do 2 pounds in a breadmaker in 15 minutes if you're careful. Lots of heat at the beginning is the key because once the beans start expanding in volume, they get very close to the heat source, so you have to dial it down.

http://forum.home...ead_id=817

But I admit, I don't wanna do it in a breadmaker.

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
John Despres
Brian, Thanks for the cyclone tip. That will be a huge help! I may need to contact Mr Pentz; to find out if less air movement will work with his designs. I looked at a small 3K gas roaster yesterday and got a bit of a handle on the cyclone.

Bill, that's great information! It's a great help with Chad's most excellent post and gets me moving in the right direction.

I have spare time this afternoon and will get started on some drawings. Getting the roasted beans out is posing a mental challenge for me. Pencil to paper may help one way or the other.

Thanks, guys, for your input.s:2
Edited by John Despres on 10/09/2008 9:03 AM
Respect the bean.
John Despres
Fresh Roast 8, Gene Cafe, JYTT 1k, Quest M3, Mazzer Mini, Technivorm, various size presses and many more brewers.
John Despres
This colander drum idea doesn't look like it's going to work very well. It's the curved bottoms. There's no problem at one end, but the other poses more problems than I can think about.

Here are 6 drawings of the colander drum in dumping positions. Note the odd design of the housing I'd have to go with.

The square at the left is the motor - I was thinking of a cam that would lock in when the drum is in roasting position.

The bearing is near the bottom of the drum and I had the idea I'd use that as my fulcrum to tip since I can't put any permanent axles on it.

Anyway, this idea is going by the wayside. I'll start looking for a nice large stainless steel pasta strainer. Something that will comfortably hold 2 pounds of beans.

I have two very nice colanders for cooling now, though.

Here's the drum in its level roasting position.
John Despres attached the following image:
Drum tip 0[1101].jpg

Respect the bean.
John Despres
Fresh Roast 8, Gene Cafe, JYTT 1k, Quest M3, Mazzer Mini, Technivorm, various size presses and many more brewers.
John Despres
First part of the dump...
John Despres attached the following image:
Drum tip 1[1102].jpg

Respect the bean.
John Despres
Fresh Roast 8, Gene Cafe, JYTT 1k, Quest M3, Mazzer Mini, Technivorm, various size presses and many more brewers.
John Despres
Middle of the dump tilt
John Despres attached the following image:
Drum tip 3[1103].jpg

Respect the bean.
John Despres
Fresh Roast 8, Gene Cafe, JYTT 1k, Quest M3, Mazzer Mini, Technivorm, various size presses and many more brewers.
John Despres
And the end.
John Despres attached the following image:
Drum tip 5[1104].jpg

Respect the bean.
John Despres
Fresh Roast 8, Gene Cafe, JYTT 1k, Quest M3, Mazzer Mini, Technivorm, various size presses and many more brewers.
John Despres
This is a bit more in line with what I'm thinking. Now to find that big ole pasta strainer...

Looks a bit like a locomotive, doesn't it?
John Despres attached the following image:
Pasta strainer locomotive[1105].jpg

Respect the bean.
John Despres
Fresh Roast 8, Gene Cafe, JYTT 1k, Quest M3, Mazzer Mini, Technivorm, various size presses and many more brewers.
Dan
John, Except for the little boggy wheels supporting the drum, this is a traditional drum roaster. The typical way of supporting the front of the drum is to run the shaft all the way through the drum and into a bearing on the front plate. You could also mount the boggy wheels on the inside of the front plate and let the rim of the strainer rest on them.

That's what I did for my parts washer I'm building. Dan
John Despres
Yes, I'm trying to build a fairly traditional roaster. Thanks for the drum shaft tip! A most useful idea I will certainly use.

Thanks, Dan!
Edited by John Despres on 10/11/2008 5:48 PM
Respect the bean.
John Despres
Fresh Roast 8, Gene Cafe, JYTT 1k, Quest M3, Mazzer Mini, Technivorm, various size presses and many more brewers.
seedlings
Any progress in the last couple of months, John?

CHAD
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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