Questions for Commercial Roasters in the know

[WSullivan]

Hey guys,

This is mainly aimed at those who own and use commercial roasters, im looking for a detailed description from those who know.....from experience so to ensure the thread gets seen , id appreciate holding out on the banter for a bit.....cheers guys

Ive seen the process quite a few times now, i just have a limited knowledge of what is actually happening as far as exhaust settings, airflow v power/gas levels etc, and how they impact on each other.

Is heat generally under the drum? or is it piped through with fans?

Are most commercial drums solid or perforated?

Mechanically, how does the load and dump of the beans actually work, i know there are 2 doors into the drum, but with a rotating drum......how does it work?

Ive been hunting around the net for a simple diagram of a roaster with airflow and component details......do you think i can find one!

You may have guessed that i have a vision of building a homemade gas roaster, itll be a while off, but i wouldnt mind tinkering with some designs/ideas on paper in the meantime.....looking to roast at least 1.3kg green....

Thanks in advance anyone who helps and offers advice stay tuned! 8-)

cheers
warren

[Fresh_Coffee]

Re: Questions for Commercial Roasters in the know

Hey guys...

1) Is heat generally under the drum? or

2) is it piped through with fans?

3) Are most commercial drums solid or perforated?

4) Mechanically, how does the load and dump of the beans actually work, i know there are 2 doors into the drum, but with a rotating drum......how does it work?

cheers
warren

Depends on type , design, age, brand , size of drum batch roaster involved but generally.....

1) yes but not always (eg some machines have combustion chamber at side). Note some machines have burners directly heating the drum, others have a separate combustion chamber, but all mostly underneath.


2) yes. "exhaust" fan at top of roaster pulls the hot air through...works like an "extractor".

3) solid

4) from the front "face" of the drum. At the front end, the drum is "open". That is, the drum is not a completely enclosed cylinder, it is kind of like a garbage bin. The open end is the front end. So when you open the door at the bottom of the front the roasted beans come out, and when you open the door at the top of the front the green beens fall in. Dont open them both at the same time  

Am sure if Ive not explained correctly someone else will chime in.

Regardz,
Attilio.

[WSullivan]

Re: Questions for Commercial Roasters in the know

ahhh that is awesome attilio!, very interesting about the more modern roasters heating method! WOW

and the face of the drum now seems obvious.......makes perfect sence

all great info, thanks a million.....

Anyone got any experience in attempting to build this type of home roaster? any tips from the pros?


Thanks heaps guys, the more info the better

PS does anyone have any of the pictures i was talking about above?

Ive been hunting around the net for a simple diagram of a roaster with airflow and component details......do you think i can find one!

[WSullivan]

Re: Questions for Commercial Roasters in the know

PPS, if anyone is thinking of carrying out a simular project and has questions feel free to jump in and ask the brains trust(pros), that way anything i forget to ask wont be missed ;D

[A_M]

Re: Questions for Commercial Roasters in the know

PPS, if anyone is thinking of carrying out a simular project and has questions feel free to jump in and ask the brains trust(pros), that way anything i forget to ask wont be missed ;D

PS. When ya dropping off ya TO ?

Ya can then have a look at the old gas fired 2kg roaster I have out back... Intended use is that of a pot plant stand..

[cuppacoffee]

Re: Questions for Commercial Roasters in the know

Just in addition to Atillios reply, a number of roasters employ a perforations at the back of the drum to optimise airflow.

Ive been hunting around the net for a simple diagram of a roaster with airflow and component details......do you think i can find one!

http://www.probatburns.com/images/probatone_diagram.jpg

Dont open them both at the same time

Done this more than once. :-[ ;D

[maheel]

Re: Questions for Commercial Roasters in the know

1st Thanks Warren

2nd i have a question that might help a build

how do the beans come out once roasted?

Is the drum of a commercial roaster level and the stirrers push it out or is the drum tilted a bit and they "fall" out?

Thanks

Leeham

[Fresh_Coffee]

Re: Questions for Commercial Roasters in the know



the drum is level and the paddles direct it outwards when the door is opened.

[runfast]

Re: Questions for Commercial Roasters in the know

Ive been hunting around the net for a simple diagram of a roaster with airflow and component details......do you think i can find one!  

This is a diagram of a Probat Probatone (solid drum)

[Koffee_Kosmo]

Re: Questions for Commercial Roasters in the know

the drum is level and the paddles direct it outwards when the door is opened.

Think in the lines of
The Archimedes-screw

http://www.google.com/imgres?imgurl=http://upload.wikimedia.org/wikipedia/commons/a/a1/Archimedes-screw_one-screw-threads_with-ball_3D-view_animated.gif&imgrefurl=http://commons.wikimedia.org/wiki/File:Archimedes-screw_one-screw-threads_with-ball_3D-view_animated.gif&h=365&w=505&sz=3560&tbnid=HRBcZW WBKIINdM:&tbnh=94&tbnw=130&prev=/images%3Fq%3DThe%2BArchimedes%2BScrew&hl=en&usg=__ 1ujMs9srITt7WBA_vHriRCUFMSU=&ei=sMiqS770A4ugkQXmk_ nGBA&sa=X&oi=image_result&resnum=3&ct=image&ved=0C AwQ9QEwAg



KK

[3fun]

Re: Questions for Commercial Roasters in the know

Is there like a baffle type thing to prevent direct heating to one spot of the drum for to long, like to try and spread the heat of the burners more? I too am trying to build a drum roaster looking at about the 1-2 kilo range.

[fancypants]

Re: Questions for Commercial Roasters in the know

Warren,

I reckon you should give Roger from Supreme Roasters a call. If youre super nice to him he might let you come around to poke and prod his new 15kg roaster (I hope Im not speaking out of school here). And hes not too far from you either.

Hes passionate enough and probably keen to share his enthusiasm.

[cuppacoffee]

Re: Questions for Commercial Roasters in the know

Is there like a baffle type thing to prevent direct heating to one spot of the drum for to long, like to try and spread the heat of the burners more?

Uhm, the drum rotates. Stopping the rotation while the drum is hot would not be a good idea.

Not trying to rain on anyones parade, but a lot of these questions have been asked and answered previously.

There is no reason why someone cant build their own roaster though its doubtful you will get it right the first time unless you have a blueprint of a commercial roaster available.

The drum is of a particular length and diameter to suit a number of variables, eg. capacity, burner configuration, etc. The baffles are designed to move the coffee forward at a certain rate. The drum itself rotates at a determined speed that will create a wave effect ie. too fast and the coffee will be plastered up against the wall of the drum, while too slow and the beans will remain in continuous contact with the drum and slide.

Fans that pull too much air through the drum, I think are detrimental rather than beneficial; how thick, and what material you use will have an effect on the outcome, and the list goes on and on.

If I were wanting to have a 2kg roaster, Id pay the asking price of something commercial and proven, or content myself with something like fatboys bbq roaster setup.

Either way, I reckon you get what you pay for.

[WSullivan]

Re: Questions for Commercial Roasters in the know

Not trying to rain on anyones parade, but a lot of these questions have been asked and answered previously.

Every question in the world has been asked before dennis ;D its just not easy to get ALL the answers i was after

If I were wanting to have a 2kg roaster, Id pay the asking price of something commercial and proven

Unfortunatly the money i have is well and truly tied up in property, 5k is not justifiable at the moment, plus im a tinker...er and i love to play and whether it works or not, ill have a ball trying, i 100% understand what your saying, the ppl designing these commercial roaster have been trying, testing and perfecting for scores of years......im just a noob :

Either way, I reckon you get what you pay for

Always true dennis, i understand that......cheers heaps for your input, i really appreciate it

regards
warren

[stuartgrant]

Re: Questions for Commercial Roasters in the know

Hi Warren,

"No Im Spartacus... I mean also planning a drum roaster build..."

Youll find heaps of useful threads over on homeroasters.org - many clever people have succeeded in what the rest of us are aiming for!

Just to add to the replies above regarding Q.4 (how the vanes work). I asked the same question somewhere on HR.org and got my head around it from the responses. Like Attilio said, the drum is level, and the vanes are angled to push the beans forward. Because of this, the beans become more piled up towards the front door than the other end. BUT some roasters have a second set of axial vanes - attached to the axle of the drum rather than the walls - which pull beans away from the door. Axial vanes only scoops up beans from the top of the pile, so when the door is opened, the axial vanes no longer reach the beans and the beans can all be scooped out by the normal vanes.

I hope that made sense. If not - Dennis has a picture of a Diedrich drum which hes posted before I believe? It shows the axial vanes nicely.


Also, regarding Q.1 (wheres the heat?), both the Diedrich and Probat websites have some decent info on how theyre fired. Diedrich IR-series use a very indirect heating method whereas Probat and many others are directly-fired. Ive heard people say that its almost impossible to get scorching on a Diedrich (though Im sure its an exaggeration) - Ive also heard people say that you need the extra guts of the direct-fired types to have "real" control... so there are pros and cons, Im sure.

Im not really in the know, but I thought Id add what Ive found out so far.
Cheers
Stu.