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Rotational Axis Roaster
klemenv
Top  #1 Print Post
Posted on 02/22/2010 1:41 AM
Hi,

first I would like to thanks to you guys for sharing information. Special thanks to Rob.

Before I have read notes regarding Rob's Air Roaster, I came accross Rotational Axis Roaster.

http://coffeedyna...oducts.php

What do you guys think of this rotational movement?

Does anybody have a clue, how it is made and if it is worth doing? Is it just horizontal air stream, or they are using some sort or mechanical rotational movement? Rotational movement could be powered by air stream. Imagine "jet roasted coffee" smile

What do you think, is rotational axis roaster providing better roast?

[Mod edit - made link clickable]
Edited by Koffee Kosmo on 02/22/2010 6:07 AM
 
John Despres
Top  #2 Print Post
Posted on 02/22/2010 6:36 AM
I have no idea, Klemen.

I looked around for more information and found one more video, but that's it.

It has settings for 3 profiles and 2 bean sizes so it must be great. The sales pitch gives the impression this machine cannot screw up a roast. Really?

All in all, it looks great and the coffee that came out looked evenly roasted. I hope someone here finds out more about it.

Check their news page - it looks like they have fun at Coffee Lab.

John
Respect the bean.
John Despres
Fresh Roast 8, Gene Cafe, JYTT 1k, Quest M3, Mazzer Mini, Technivorm, various size presses and many more brewers.
 
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seedlings
Top  #3 Print Post
Posted on 02/22/2010 8:14 AM
My first impression, based on their info is skeptical. Mostly because of this line, which I believe to be misleading:

"The new Coffee Lab Rotational Axis Roaster addresses the technical problems with both drum-style roasters and most of the current "fluid bed" roasters. The latter have very poor heat transfer characteristics that require greatly elevated inlet air temperatures, which are known to damage the delicate flavor elements of coffee beans."

As there are professional/industrial hot-air roasters whose independent cupping scores are as high or higher than drum roasts for the same bean.

In my opinion, statements like this are either made in ignorance or in deceit. Either of which make me wonder. The video seems to mediocre circulation, especially before the beans lose weight and brown.

But, I'd take one!

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
oceanacoffee
Top  #4 Print Post
Posted on 02/22/2010 9:16 AM
Hi,
I just had a quick look at the video of this machine. I can't say that there is anything impressive or different or new technology, seems like a clever play on technical words !!
Axial Roasting !! Anything going around the same axis, whether air driven, donkey driven or mechanically driven can be called the same break through technology.
At 1st glance it looks like a fluid bed air roaster.
Just a quick note, my background is Marne Engineering, I am always checking out new ideas for roasting & roasters.
On saying that I have seen the same bean movement behavior for a roaster in a converted Poppery 2.
How to roast coffee is not a secret, what type of machine & the construction is not a technology secret.
What will be the break through will be efficiency, cost to build, cost to buy, cost to roast.
So he built a very flash Poppery !!
Hahaha
Edited by oceanacoffee on 02/22/2010 9:16 AM
 
Hamilton
Top  #5 Print Post
Posted on 02/22/2010 5:10 PM

Quote

seedlings wrote:
My first impression, based on their info is skeptical. Mostly because of this line, which I believe to be misleading:

"The new Coffee Lab Rotational Axis Roaster addresses the technical problems with both drum-style roasters and most of the current "fluid bed" roasters. The latter have very poor heat transfer characteristics that require greatly elevated inlet air temperatures, which are known to damage the delicate flavor elements of coffee beans."

As there are professional/industrial hot-air roasters whose independent cupping scores are as high or higher than drum roasts for the same bean.

In my opinion, statements like this are either made in ignorance or in deceit. Either of which make me wonder. The video seems to mediocre circulation, especially before the beans lose weight and brown.

But, I'd take one!

CHAD


I agree. This quote:
"Our roaster keeps the beans in constant contact, just like the particles of a fluid, and moving at a uniform speed to ensure consistent temperatures."

Makes me skeptical of either what I learned in physics classes, or these guys.

Very nice fit and finish, though.
 
nufsaid
Top  #6 Print Post
Posted on 02/22/2010 6:42 PM
from the drawing it looks like a roaster I saw on you tube built by dirty daves-san fransico. Any thoughts?
 
RoasterRob
Top  #7 Print Post
Posted on 02/22/2010 7:11 PM
Yup not to mention being very similar to the Neuhaus Lab roaster. Yours for 15000 Euros - how do they do it so cheap?

http://coffeesnob...409344/4#4

Gee my roaster rotates coffee the wrong way.

[video]http://www.youtube.com/watch?v=wIOZRlliQ2U[/video]

Rob
Edited by RoasterRob on 02/22/2010 7:13 PM
VBM Minimax 2gp, 1gp Reneka Techno, 2 gp la Pavoni Pub, la Cimbali M28, SJ Maz, FB 6kg HM roaster and other stuff
 
seedlings
Top  #8 Print Post
Posted on 02/22/2010 8:34 PM

Quote

RoasterRob wrote:

Gee my roaster rotates coffee the wrong way.


HA! Plus yours won't keep the beans in constant contact with each other. Shame.

Roflmao

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
klemenv
Top  #9 Print Post
Posted on 02/23/2010 12:58 AM

Quote

gerry wrote:
from the drawing it looks like a roaster I saw on you tube built by dirty daves-san fransico. Any thoughts?


I am sure it is the very same. Just like Neotec roasters. Yours trully for Grin amount of euros.

BTW, here is shown bean movement in Sivetz roaster.
http://www.javama...o-big.html

and to me, bean movement in Rob's roaster looks the best.
Edited by Koffee Kosmo on 02/23/2010 5:41 AM
 
RoasterRob
Top  #10 Print Post
Posted on 02/23/2010 3:52 AM
Maybe I should patent it. ;)

The conical RC dates back to before Sivitz. Micheal Sivitz invented and patented the Assymetrical flow RC in the 60s.
http://www.sivetz...atalog.htm
The 1/2 bag roaster gives the best idea of the RC shape.

Rob
Edited by Koffee Kosmo on 02/23/2010 5:42 AM
VBM Minimax 2gp, 1gp Reneka Techno, 2 gp la Pavoni Pub, la Cimbali M28, SJ Maz, FB 6kg HM roaster and other stuff
 
Koffee Kosmo
Top  #11 Print Post
Posted on 02/23/2010 5:44 AM
I remember something my grandmother said often when she was alive

"Everything Old is New Again" :P

KK
I home roast and I like it. Designer of the KKTO
Roaster Build information
https://homeroast...ad_id=1142

https://docs.goog...lide=id.i0
Blog - http://koffeekosm...gspot.com/

Bezzera Strega, Mazzer Robur Grinder, Pullman Tamper Convex,
(KKTO) Turbo Oven Home Roaster.
 
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allenb
Top  #12 Print Post
Posted on 02/24/2010 9:29 PM
I?m new to Homeroasters and have really enjoyed the posts I?ve read to date. I thought I?d throw in my couple of cents worth on this subject.

The Coffee Lab Rotational Axis Roaster appears to be a knock-off of technology invented and patented by Jobst Zoellner formerly of Neuhaus Neotec GmbH in Germany. After leaving Neuhaus he started a company called Nepro and calls the roaster technology ?Vortex Fluidat?. You can pull up their site and after some doing there is a video showing a little shop roaster going through the motions. (not easy to find)

The patented technology involves a special perforated plate with a repeating pattern of irregular perforations (patterns of higher density hole spacing graduating towards lesser density throughout the sheet. This pattern causes the convection air to move the beans in what is termed a ?bubble bed? versus the standard fluid bed spout. I have heard that the rotational movement is caused by the circular pattern of air entering the chamber or vanes in the top causing the discharging air to move in a spiral pattern before exiting.

The impetus for the invention was supposedly to allow what is called ?flash roasting? which is usually accomplished using fluid bed convection roasting in a very short time (seconds up to a couple of minutes). The idea behind flash roasting was to rapidly expand the beans causing much increased fractures and pores which when ground and brewed leads to an increased brew extraction but unfortunately causes an inferior cup. The inferior cup didn?t stop the big commercial roasters from using the technology since it allowed shorter roasting times (less cost per pound to roast) and the sales pitch was more brew per ounce of coffee.

I'm sure there have been prior posts covering bubble-bed (versus fluid bed) technology but for those who have not read up on it I'll do a quick overview. As we know, typical fluid bed roasters produce a spouting bed which is a rising column of beans within the bean mass. Eventually all the beans make their way into the spout path taking on convective heat.

In a bubble bed roaster most of the bean mass is in a state of suspension due to a high number of expanding and collapsing pockets of convection air around the beans. The analogy made to describe what it would look like is a pot of water at a super fast boil. The neat part of this technology is that it allows the whole bean mass to be surrounded at any given moment by the same temperature of convection air instead of the delay in a fluid bed spout waiting for the rest of the mass to finally make it?s way through the spouting column. The benefit of this is obviously the ability to roast to a given degree using a lower environment temperature than possible using standard fluid bed technology. Lower environment temperature, less thermal stress to the bean for a given roast.

The down side to building one is you have to recycle some of the exhaust stream back through the fan to keep the KW from being prohibitive. This technology requires a lot more CFM than a fluid bed.

I would challenge anyone with the ambition and drive to build one of these that they would find a superior cup due to the better heat transfer qualities. How much better? Who knows, might be surprising when you roast using your usual profiles but with lower convection air temps. I would build one but don?t have the time nor the $.

The patent for the perforated plate can be found at Free Patents on line. The plate shown is rectangular but you can use the pattern with a round plate shape. Patent info below:

Perforated bottom plate for the production of a fluidized bed.
Zoellner, Jobst O. A. (22848 Norderstedt, DE)
United States Patent 6338303
Abstract:
A perforated bottom plate for the production of a fluidized bed within a container. The perforated bottom plate has a large number of holes through which a gaseous medium flows in order to produce the fluidized bed. For better mixing of the granular material in the fluidized bed, the perforated bottom plate is provided with evenly distributed areas in which, compared to a uniform perforation, a greater number of holes per unit of area is provided.

Cheers
 
seedlings
Top  #13 Print Post
Posted on 02/25/2010 8:02 AM
Great post, Allen! That explains much better than the website.

In the video it appears, before the beans dry out and lose weight, that there is a layer of beans on the outside that just keep spinning round and round without circulating into the bean mass.

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
endlesscycles
Top  #14 Print Post
Posted on 02/25/2010 8:39 AM
I clearly see the advantages here, but also the problem you noticed, Chad. Even in Rob's design, I get a little worried about even heat application, but the result in the cup is pretty phenomenal. I do agree that there is a tricky balance of air temp and convection rate, and a balance that changes dramatically through the first crack that could be reduced by "constant contact". Recirculating heat is something I'd like to keep out of my roasters for both motor life and avoiding the jump in convection rate as the beans release moisture through first.....

just some thoughts as I'm getting dressed for work.
-Marshall Hance
Asheville, NC
 
John Despres
Top  #15 Print Post
Posted on 02/25/2010 9:13 AM
Wow, excellent first post, Allen. Welcome, welcome.

What are you roasting with at home?

John
Respect the bean.
John Despres
Fresh Roast 8, Gene Cafe, JYTT 1k, Quest M3, Mazzer Mini, Technivorm, various size presses and many more brewers.
 
Web
Hamilton
Top  #16 Print Post
Posted on 02/25/2010 1:37 PM

Quote

seedlings wrote:
In the video it appears, before the beans dry out and lose weight, that there is a layer of beans on the outside that just keep spinning round and round without circulating into the bean mass.

CHAD


I suppose I've never had coffee from this type of roaster, but that does seem like a downside. Just looking at it, I would expect uneven roasting to be an issue. Since, I'm not really aware of uneven heating being a big problem in the Sivetz or other air roasters, I'm also not sure what problem this 'bubble-bed' is trying to solve.

Just my 2 cents.
 
endlesscycles
Top  #17 Print Post
Posted on 02/25/2010 3:45 PM
The bubble bed is all about high convection rate; you can potentially get great roast profiles with lower environment temperatures, which improve bean shelf life and cup quality.

I'm curious if this could be done with a deep bean bed, as the energy inefficiency of shallow bed bead is the biggest obvious drawback. Large vent holes about the perimeter would fix the recirculation problem.
-Marshall Hance
Asheville, NC
 
allenb
Top  #18 Print Post
Posted on 02/25/2010 10:16 PM
John, I switch between a 1 lb drum and a Siemens Sirocco fluid bed which does a 1/4 lb. The drum is a home built which is more of an experimental rig with inside the drum quartz radiant and under the drum convective heat. The radiant is dialed back to just sort of steer the roast using a Fuji PXR4. The main heating is via drum heat which I like better than with radiant being primary.

The question of even heating with the bubble bed is a good one since it does look as if the perimeter band of beans is not part of the real action but from previous articles it seems this is not an issue. Even roasting has been one of their claims to fame. If you think about it, in a fluid bed, the beans migrating down outside the spout plume waiting to be picked up in the spout are not getting full convection heat. So there's probably issues with both methods but the bubble bed is supposedly superior in regards to even heat transfer. Unfortunately, the only way to know how well it would do in a home rig is to build one and do some real world experimentation.

Here's a video from Nepro showing one of their smaller rigs which appears to have pretty good bean movement:

http://www.nepro....asting.avi

In regards to recirculating the exhuast, you wouldn't need to recirculate a large percentage but at least enough to bring the temperature entering the convection heater to 200-250 F. This obviously could not be done with a popcorn style fan/heater combo since the inlet air is flowing past the motor. Instead, it would need to be a real centrifugal fan with inlet opposite the motor. The recirulating exhaust would need to meet at the fresh air inlet and you would damper the fresh air for adjusting the ratio of each. One thing of interest is that this technology does not require the high static pressures needed with a standard fluid bed since you're not shoving the air past a small opening at the bottom of a funnel. At 250 F you would not need a long shaft fan motor with slinger to protect the motor thermally. On another note, the issue of exhaust needs to be addressed. There will need to be a damper on the duct/port leaving the chaff collecting cyclone or screen box to be able to balance the recirc air versus exhaust to atmosphere air.

The bean bed depth issue endlesscycles mentioned is a good one. My take on this is it would definitely have a restriction on min/max depth for proper bubble bed action. In regards to convection rate jumping, it would probably be tough to control without PID control since, as you mentioned, the temperature would be a moving target..

Cheers
 
RoasterRob
Top  #19 Print Post
Posted on 02/26/2010 3:39 AM
Hi Allen

Great info in your posts. I can't say that I had heard of the bubble bed roaster before. Which is surprising, I have spent far too much time on the web looking at roaster design etc.
I saw the pics of your drum roaster on HB, really good work.

Rob
VBM Minimax 2gp, 1gp Reneka Techno, 2 gp la Pavoni Pub, la Cimbali M28, SJ Maz, FB 6kg HM roaster and other stuff
 
allenb
Top  #20 Print Post
Posted on 02/26/2010 10:33 AM
Rob,

Thanks for the compliments.

It was a complete accident running into articles about this technology on the web. If I recall correctly one was in a technical paper by a Japanese gentleman pointing out its merits over other methods. I'll try to locate some of these and post them.

I'm very impressed with the size and evenness of the bean plume seen in the video of your roaster. You must be getting great convection transfer uniformity which I have struggled with in some of my experimentation with fluid beds. Where can I see pics of your setup?

Allen
 
RoasterRob
Top  #21 Print Post
Posted on 02/26/2010 2:35 PM
Hi Allen Pics etc via a PM

Rob
VBM Minimax 2gp, 1gp Reneka Techno, 2 gp la Pavoni Pub, la Cimbali M28, SJ Maz, FB 6kg HM roaster and other stuff
 
allenb
Top  #22 Print Post
Posted on 02/27/2010 9:54 AM
Sorry guys. My assumption that Dirty Dave/Coffee Lab's Rotational Axis roaster was taken from Nepro's perf plate technology is false.

I found what I am pretty sure is Dirty Daves patent application. After reading about his use of tangential nozzels in the paper it now makes sense why the increased rotational speed seen in their video. I don't think Dave's design achieves nearly as good of bean mixing/agitation as Nepro's bubble bed but who knows.

Link to Dave Greenfields patent application:

http://www.faqs.o...0090304886

I also found an article I had not seen on Nepro Vortex Fluidat in this article by Reg Butler:

http://www.thefre...a068279701

The article has the usual hokie sales propaganda but one thing I find very interesting is that the Nepro roaster seems to recirculate 100% of the roasting gasses by scrubbing via a catalytic unit. Supposedly keeps oxygen from deteriorating the beans. The article also mentions what I think is an additional fan above the roasting bed that provides additional convection air movement, chaff collection and provides the force that roatates the bean mass. Unfortanately, this article has all sorts of annoying dictionary clickables to navigate through.

Cheers
 
seedlings
Top  #23 Print Post
Posted on 02/27/2010 1:26 PM

Quote

allenb wrote:
<snip>
The article has the usual hokie sales propaganda but one thing I find very interesting is that the Nepro roaster seems to recirculate 100% of the roasting gasses by scrubbing via a catalytic unit. Supposedly keeps oxygen from deteriorating the beans.
<snip>


That's what I tried to build... still on the bench...

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
klemenv
Top  #24 Print Post
Posted on 02/27/2010 5:24 PM
Hi Allen,

thanks for the information.

I have not quite understand, why bubble bed needs more CFM? Is it because of larger orifice?

Does anybody have clue, how to size vortex roaster that would roast like 1Kg batch?

Is it really necessary to recycle hot gas, or one can live with slightly larger gas consumption?
 
allenb
Top  #25 Print Post
Posted on 02/27/2010 8:37 PM

Quote

klemenv wrote:
Hi Allen,
thanks for the information.
I have not quite understand, why bubble bed needs more CFM? Is it because of larger orifice?
Does anybody have clue, how to size vortex roaster that would roast like 1Kg batch?
Is it really necessary to recycle hot gas, or one can live with slightly larger gas consumption?


Klemen,

As endlesscycles rightly put it, it is definately all about high convection rates. The difference is having a high convection flow rate across the entire surface area of the roast chamber versus a portion of the chamber. To do this requires much more CFM but not high static pressure. In some of my experimentation with fluid bed roasters I've had to have at least 10" water column to get a decent lift. I'm not sure how much less than this you could get away with to create the bubble bed action, 2", 4"?

As far as CFM for a 2 1/2 lb batch? If someone could weigh-in on what CFM is needed for this size batch in a fluid bed? Then I would start out by multiplying that by at least a factor of 5 but don't hold me to this as I have never had any experience with bubble bed design.

To size one of these roasters I'm guessing from looking at the Nepro in the video which appears to be the smaller 1 kg unit that you would want the bed height to be somewhat smaller than the diameter of the chamber but how much smaller? You'll have to experiment with varying size tin cans and a 1kg batch of green to find the right dia.

With gas heat you should be able to go without recycling the exhaust. With elecrtric you would probably dim the neighborhood to hit roasting temps.

Hope this helps,

BTW, Attached is another copy of Dirty Daves roaster patent application with drawings.
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
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