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CoffeeAir II Roaster Build
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| SteveN |
Posted on 09/30/2010 07:13
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1/4 Pounder
Posts: 128
Joined: 03/16/2010 19:36
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Any idea as to how much more power you'd want to do the 2# unassisted (no blocking airflow)? I'm interested, obviously, since my roaster is based fairly closely to your design. |
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| seedlings |
Posted on 09/30/2010 07:29
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Administrator EMERITUS
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Joined: 06/27/2007 11:39
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Steve, I'd like to have double the heat power. That would be overkill, but... more than enough is always enough. I'd like to be able to re-circulate a portion of the hot air, which should give the boost I need in the 300F-375F range. If I could open a damper to allow the hot air intake, then close it before the onset of first crack, that's the boost I want. Really, I'm happy with these curves. If I want to go a little faster, I'd just lighten the load slightly.
CHAD
Edited by seedlings on 09/30/2010 07:31
Don't put the cart before the horse. Put the horse in the cart and listen to him say "weeeee" all the way down the hill.
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| dja |
Posted on 09/30/2010 08:40
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1 1/2 Pounder
Posts: 734
Joined: 11/07/2008 09:34
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You would need a top for your roaster with two outlets on it, and probably have to have dampers in both sides, that way you could push as much exhaust air as you wanted to back thru the VC Motor. you will also have to have your VC opening partially open.
What are you planing on for the chaff, it will have to be removed before it hits the heating element?.
I would make a V connection out of some 2", 062, wall tubing and weld it to a plate, then make me a couple dampers, (like the throttle plates in a Carburator) put one in each side. you put em in there right and u could tie them to gether so they would open and close at the same time, lenght of arms would determine the timing.
I pour Iron and roast Coffee Beans 
If life seems normal your not going fast enough Mario Andrette |
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| seedlings |
Posted on 10/01/2010 16:05
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Administrator EMERITUS
Posts: 4295
Joined: 06/27/2007 11:39
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Let me say that having 30 pounds of test coffee is THE WAY to figure out your new roaster. I'm confident now that this roaster is capable of 2# loads - and having an auto-logger so I don't have to write or click a mouse every few degrees would give more control.
2 Pounds, 450F preheat, set temp 630F (took 11:00 to get there):
First Crack starts at 10:00, outliers before that, and 2nd crack started at 13:52, but I could have stretched that out. The zig-zags in the blue ET graph correspond to blower adjustments, until just before first crack, when the blower was at the lowest setting.
What I've learned:
1) the beans respond very well when the ET is 200F or more above BT
2) the heaters must operate at full power until somewhere around the end of first crack
3) drying phase can be stretched or shortened, time between cracks can be stretched or shortened, but 300F-400F can not be shortened without reducing bean load
4) partially covering the top of the hopper is a must, and shortens roast time
5) for a smooth ET curve, circulation needs almost continuous, slow, adjustment down, until about first crack, when the blower is at the lowest setting
6) 2 pounds of beans produce a significant amount of chaff
7) concern that lower ambient temperatures might extend roast times
CHAD
Edited by seedlings on 10/01/2010 16:13
Don't put the cart before the horse. Put the horse in the cart and listen to him say "weeeee" all the way down the hill.
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| Unta |
Posted on 10/01/2010 16:22
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Moderator
Posts: 802
Joined: 01/26/2010 17:44
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Seedlings Wrote:Let me say that having 30 pounds of test coffee is THE WAY to figure out your new roaster. I'm confident now that this roaster is capable of 2# loads - and having an auto-logger so I don't have to write or click a mouse every few degrees would give more control.
well thats good news.. any idea about chaffe collection? I was thinking about the temp issue and I have significantly lower out air temps. What are your post bean air temp readings?
sean
Sean Harrington
educate.
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| seedlings |
Posted on 10/01/2010 17:53
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Administrator EMERITUS
Posts: 4295
Joined: 06/27/2007 11:39
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I haven't measured the air exiting the roaster, but my original plan was to have a blower fan above the roaster and have the chaff blow outside for the birds to eat. A vent, like on the clothes dryer. A chaff collector wouldn't be too tough to build, but I'll cross that bridge later.
CHAD
Don't put the cart before the horse. Put the horse in the cart and listen to him say "weeeee" all the way down the hill.
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| RoasterRob |
Posted on 10/03/2010 02:58
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1/2 Pounder
Posts: 318
Joined: 03/03/2007 22:30
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First Crack starts at 10:00, outliers before that, and 2nd crack started at 13:52, but I could have stretched that out. The zig-zags in the blue ET graph correspond to blower adjustments, until just before first crack, when the blower was at the lowest setting.
What I've learned:
1) the beans respond very well when the ET is 200F or more above BT
2) the heaters must operate at full power until somewhere around the end of first crack
3) drying phase can be stretched or shortened, time between cracks can be stretched or shortened, but 300F-400F can not be shortened without reducing bean load
Hi Chad
Is this hooked to the pid or manual control? Are you aiming for a roast time of near 14 minutes or is this as fast as the roaster will get there? Your ROR seems a bit fast to 300, then a bit slow from 300 to right thru to dump. Based on the RC size 2lbs might be a stretch.
4) partially covering the top of the hopper is a must, and shortens roast time
Does covering the top of the RC affect the airflow and thus the bean movement?
5) for a smooth ET curve, circulation needs almost continuous, slow, adjustment down, until about first crack, when the blower is at the lowest setting
Yup. I turn mine down almost mm by mm. To me having a pid didn’t seem that useful unless it was operating as the fan control.
6) 2 pounds of beans produce a significant amount of chaff
You want see what 5lbs does for chaff, (soon to be 13 lbs)
7) concern that lower ambient temperatures might extend roast times
yes it will
Rob vL
NZ
Edited by RoasterRob on 10/03/2010 03:00
VBM Minimax 2gp, 1gp Reneka Techno, 2 gp la Pavoni Pub, la Cimbali M28, SJ Maz, FB 6kg HM roaster and other stuff
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| seedlings |
Posted on 10/04/2010 06:43
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Administrator EMERITUS
Posts: 4295
Joined: 06/27/2007 11:39
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RoasterRob wrote:
Hi Chad
Is this hooked to the pid or manual control? Are you aiming for a roast time of near 14 minutes or is this as fast as the roaster will get there? Your ROR seems a bit fast to 300, then a bit slow from 300 to right thru to dump. Based on the RC size 2lbs might be a stretch.
Right now the heat is full-on, so PID won't help, except... I could easily extend the drying time to 300 by keeping the set temp at 500 for X minutes before going to full power. I like the ability to get to first crack in 10 minutes... from there I can extend times as needed. 2lbs is the outer limit, agreed.
Does covering the top of the RC affect the airflow and thus the bean movement?
No. I don't block enough off to change flow or circulation. My guess is that it keeps a 'cushion' of hot air above the beans (but that might be my imagination).
You want see what 5lbs does for chaff, (soon to be 13 lbs)
HA! The Rwanda I roasted Friday night was like nuclear fallout! With no breeze outside it left an even coating on the garage, mower, sidewalk, yard, my hair, the laptop...
seedlings wrote: 7) concern that lower ambient temperatures might extend roast times
yes it will
I figured. Need to get partial recirculation up and running.
CHAD
Don't put the cart before the horse. Put the horse in the cart and listen to him say "weeeee" all the way down the hill.
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| freshbeans |
Posted on 10/04/2010 06:54
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Super Admin
Reasonable
Posts: 1400
Joined: 03/06/2010 11:10
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Hi Chad,
Looking forward to the video!!
On the recirc; In the past, I used the exhaust line as a sort of heat exchanger by sleeving it with larger duct. Using the 'sleeve' air as intake air for the blower really helped during the winter. It's not a recirc, but it helped.
Good Luck -Scott |
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| seedlings |
Posted on 10/04/2010 07:55
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Administrator EMERITUS
Posts: 4295
Joined: 06/27/2007 11:39
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freshbeans wrote:
Hi Chad,
Looking forward to the video!!
-Scott
J. J. Abrams turned me down (something about 'profit' or whatever), Tarantino and the Coen Brothers haven't called back yet.
CHAD
Don't put the cart before the horse. Put the horse in the cart and listen to him say "weeeee" all the way down the hill.
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| Unta |
Posted on 10/04/2010 08:03
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Moderator
Posts: 802
Joined: 01/26/2010 17:44
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qunetin will just add zombies..I'd go Coen.
my 2 cents.
sean
Sean Harrington
educate.
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| freshbeans |
Posted on 10/04/2010 08:20
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Super Admin
Reasonable
Posts: 1400
Joined: 03/06/2010 11:10
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Obviously, they have not seen the 'Sierra Mist Depth Charge'.
Who needs them anyway! ...Punks. -Scott |
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| seedlings |
Posted on 11/04/2010 20:03
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Administrator EMERITUS
Posts: 4295
Joined: 06/27/2007 11:39
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1.75# is the perfect charge for this roaster... with ambient temps above 60F. With today's high winds and 50s temps the air temp stalled at 583F. A buddy was over roasting, so his Rwanda took 5 minutes to get from 405 (rolling first crack) to 430F final temp. Honestly, I don't know if it would've made it to second crack without recirculation.
I'll post another video soon of an entire roast (since youtube upped the time limit).
CHAD
Edited by seedlings on 11/04/2010 20:03
Don't put the cart before the horse. Put the horse in the cart and listen to him say "weeeee" all the way down the hill.
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| greencardigan |
Posted on 11/23/2010 21:41
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Pounder Plus
Posts: 538
Joined: 11/21/2010 20:23
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Any updates on this one??
I am liking the square design. And I sense I might be building a copy in the near future. :BowDown: |
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| seedlings |
Posted on 11/24/2010 10:06
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Administrator EMERITUS
Posts: 4295
Joined: 06/27/2007 11:39
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greencardigan wrote:
Any updates on this one??
I am liking the square design. And I sense I might be building a copy in the near future. :BowDown:
Hey, welcome to the forums, and thanks for asking! It works great. The PID on the heat is completely unnecessary. I leave it on full power and adjust the airflow down, which increases the heat. It was in the low 40s when I roasted a couple of days ago. I was roasting 1.75# and the ramp from 300F-400F was going a little slow due to the cold. I turned the heatgun on low and pointed it at the roaster's inlet and watched the air temp jump 20 degrees. I had the heatgun far enough away from the inlet that I could hold my hand there. It was hot... maybe 120F? But not like roasting temperatures. I really want to work on partial recirculation of heat... with that I might be able to roast up to 3 pounds....? Who knows.
It's a very fun project!
CHAD
Don't put the cart before the horse. Put the horse in the cart and listen to him say "weeeee" all the way down the hill.
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| greencardigan |
Posted on 11/25/2010 22:05
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Pounder Plus
Posts: 538
Joined: 11/21/2010 20:23
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A quick question.
How is the RC attached to the base/heater section? In the your pics it looks like it's just sitting on top?
Edited by greencardigan on 11/25/2010 22:07
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| seedlings |
Posted on 11/26/2010 17:18
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Administrator EMERITUS
Posts: 4295
Joined: 06/27/2007 11:39
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greencardigan wrote:
A quick question.
How is the RC attached to the base/heater section? In the your pics it looks like it's just sitting on top?
Gravity keeps it together. Takes a heck of a blower to launch 2# of beans plus 5# of steel and glass off the top- blowing through perforations...
Yep, that'll do it. If your hopper were significantly lighter, there may be an issue.
CHAD
Don't put the cart before the horse. Put the horse in the cart and listen to him say "weeeee" all the way down the hill.
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| RoasterRob |
Posted on 11/26/2010 17:37
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1/2 Pounder
Posts: 318
Joined: 03/03/2007 22:30
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seedlings wrote:
...... It works great. The PID on the heat is completely unnecessary. I leave it on full power and adjust the airflow down, which increases the heat.......
;)
VBM Minimax 2gp, 1gp Reneka Techno, 2 gp la Pavoni Pub, la Cimbali M28, SJ Maz, FB 6kg HM roaster and other stuff
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| seedlings |
Posted on 11/26/2010 17:39
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Administrator EMERITUS
Posts: 4295
Joined: 06/27/2007 11:39
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Yes, I know you told us so, Rob... I just wanted to... be....
...cool.
B)
CHAD
Don't put the cart before the horse. Put the horse in the cart and listen to him say "weeeee" all the way down the hill.
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| RoasterRob |
Posted on 11/26/2010 18:46
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1/2 Pounder
Posts: 318
Joined: 03/03/2007 22:30
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I guess the ;) wasn't really that subtle.
Cool is overrated. This is Zen PID - be the PID. The ideal for control on this type of roaster (IMO) without going to a form of full automation of fan and heat is to have the fan controlled by a PID/PLC based on BMT and a manual fine control on the fan. Then the roaster would practically follow a profile which you could tweak with the fan fine control or the heat source control if it was slightly out because of ambient temp etc.
Rob
VBM Minimax 2gp, 1gp Reneka Techno, 2 gp la Pavoni Pub, la Cimbali M28, SJ Maz, FB 6kg HM roaster and other stuff
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