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High agitation radiant roaster
farmroast
I've been working up a new roaster design. It uses a couple of the concepts of my Dreamroast homebuilt. But instead of being primarily convection I want to add more radiant heat application. I'm planning on using my bean bat high speed whirling of the beans for great agitation and even roasting. Instead of adding the convection/turbo oven top on the top of the pot I want to place a heating element in the middle of the pot to utilize the radiance off the element. For a simple off the shelf element I'm considering a heat gun replacement element. The can be had for $20-50. I will add a stainless steel screen around the element. I will use my chaff canister and slit in the roasting pot side to collect the chaff. I'm not sure a fan will be necessary as the high speed bean flow may add enough of the convection needed. This will conserve heat. If needed a small fan could be added to the lid.

I'm still at the early stage of the concept but think it may have some potential. Shooting for a full lb. batch size that could be enlarged to do larger roasts using more than one element and a larger pot.
Ed B.
DreamRoast 1kg roaster, Levers, Hand Mills http://coffee-roa...gspot.com/
 
allenb
One option for a good radiant source (and not too expensive) is a stovetop tubular in a 120 volt version. You can buy the reflector/pan that normally sits below it in a stovetop setup to place above it to limit upward heat radiation and force most of the heat down to the coffee bed. I've done some crude experimentation using this setup and is very effective. For a 1 pound load you will only need 800-1000 watts during the first phase of the roast. Getting the nichrome heatgun element to focus most of it's heat on the coffee might be difficult.

A convection fan shouldn't be necessary unless needed to help with chaff separation.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
Koffee Kosmo
With my 2 pot system it is possible to add another heat element to the underside of the beans
This extra heat will be used in conjunction with the Turbo Oven and use all of its features as it is now

Something like this but using a spiral type oven fan element
Entry is from the side with its own power plug

KK
Koffee Kosmo attached the following image:
3268696755_0c814de3f9.jpg

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.
 
farmroast

Quote

Koffee Kosmo wrote:
With my 2 pot system it is possible to add another heat element to the underside of the beans
This extra heat will be used in conjunction with the Turbo Oven and use all of its features as it is now

Something like this but using a spiral type oven fan element
Entry is from the side with its own power plug

KK
I have the plate heater on the bottom of my Dreamroast to supplement and balance the heat. It's embedded in a plate of aluminum to spread the heat.
farmroast attached the following image:
dreamro684[297]_1.jpg

Edited by farmroast on 10/16/2010 7:51 PM
Ed B.
DreamRoast 1kg roaster, Levers, Hand Mills http://coffee-roa...gspot.com/
 
farmroast

Quote

allenb wrote:
One option for a good radiant source (and not too expensive) is a stovetop tubular in a 120 volt version. You can buy the reflector/pan that normally sits below it in a stovetop setup to place above it to limit upward heat radiation and force most of the heat down to the coffee bed. I've done some crude experimentation using this setup and is very effective. For a 1 pound load you will only need 800-1000 watts during the first phase of the roast. Getting the nichrome heatgun element to focus most of it's heat on the coffee might be difficult.

A convection fan shouldn't be necessary unless needed to help with chaff separation.

Allen
The beans whirl around the outside walls of the roast pot on my roaster, not on the bottom as with the other TO design stir roasters, so the cylinder shaper heat gun element would have nice exposure like being in the center of a doughnut of beans.
Edited by farmroast on 10/16/2010 8:11 PM
Ed B.
DreamRoast 1kg roaster, Levers, Hand Mills http://coffee-roa...gspot.com/
 
allenb
Got it.

Have you ever seen these nichrome radiant heater elements by Eagle (now Cooper). I've used them before and they're pretty indestructible. Not sure where to get them these days. Unfortunately, you'd have to mount it fat side up but you could remove the medium base threaded metal piece and wire direct. Sivetz use to use them in his smaller fluidbeds.

http://www.portic...heater.pdf
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
seedlings
Ed, it sounds like you're not adding airflow, but adding more heat sources? Will air be flowing across the heat element, or will the high speed bean action provide air circulation?

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

Quote

seedlings wrote:
Ed, it sounds like you're not adding airflow, but adding more heat sources? Will air be flowing across the heat element, or will the high speed bean action provide air circulation?

CHAD

This roaster will not have a TO top, just a lid with the element/s attached to it, going down into the middle of the pot.
Been pondering air flow. I was thinking that the bean action might be enough (200+rpm). Or A little fan could be mounted on the top. I want as much radiant effect on the roast as possible with good mixing. Radiant heat and roasting almost anything just seems to make the most sense.
Edited by farmroast on 10/17/2010 7:19 PM
Ed B.
DreamRoast 1kg roaster, Levers, Hand Mills http://coffee-roa...gspot.com/
 
John Despres
Hmmm. 200+ RPM seems to me as though the beans will be "glued" to the sides of the pot, leaving one side of the bean facing the element and the other in contact with the pot. Will they tumble at all?

I think I'm missing something.

John
Edited by John Despres on 10/17/2010 10:37 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.
 
farmroast

Quote

John Despres wrote:
Hmmm. 200+ RPM seems to me as though the beans will be "glued" to the sides of the pot, leaving one side of the bean facing the element and the other in contact with the pot. Will they tumble at all?

I think I'm missing something.

John

John
In a typical drum roaster, high speed will glue the beans to the wall with centrifugal force. In the vertical Dreamroast pot the high speed bean bats (2.25mm) bat the beans upwards towards the side of the pot and as gravity pulls the mass downward keeps batting the mass off of the bottom, upward. This keeps the beans moving and churning, rapidly. The key to good agitation, evenness and heat transfer efficiency.
Ed B.
DreamRoast 1kg roaster, Levers, Hand Mills http://coffee-roa...gspot.com/
 
John Despres
Aye. Got it, Ed.

I thought there must be some sort of agitation in there, but missed it, I guess.

After everything I've seen you post here and elsewhere, I was certain you had it figured out, but needed to ask.

Thanks for clarifying. I'm looking forward to progress reports.

Another question: As the beans fall back to the bottom to begin their journey up again, is there any concern about the beans touching the heat element? Is the pot big enough to to avoid contact or would the contact be so short, it wouldn't matter?

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.
 
seedlings
Ditto John's 'another question'. In my mind you'll need airflow, but I'm sure you've conceptualized far beyond what I'm considering. Excited to see this one take shape.

CHAD
Edited by seedlings on 10/18/2010 6:24 PM
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
Sanvito
I am new at this forum, I really enjoyed reading it
 
John Despres
Hiya! Welcome Sanvito! This is indeed a fun place.

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.
 
farmroast
The beans or chaff rarely get near the middle but plan on putting a cylinder of SS screen around it. I'm looking at elements from Master Appliance guns. There is a model heat gun that looks like a hair dryer and one the call a heat blower that might be a little larger in diameter. I cant find dimensions of the elements listed anywhere. The gun element seems to be mounted on ceramic where the blower one appears to be mica based.
farmroast attached the following image:
heat-gun-element-kit-1a502_as01.jpg

Ed B.
DreamRoast 1kg roaster, Levers, Hand Mills http://coffee-roa...gspot.com/
 
farmroast
The one above was the ceramic and this is the heat blower one
Anyone have a Master heat gun that could give me the size of the element?
fyi The heat blower model looks like this http://www.master...sflow.html
Probably not enough blower push to be considered for a fluid bed homebuilt of much size
farmroast attached the following image:
30358_300.jpg

Edited by farmroast on 10/18/2010 7:47 PM
Ed B.
DreamRoast 1kg roaster, Levers, Hand Mills http://coffee-roa...gspot.com/
 
Koffee Kosmo
You can use a whole type cake pan that will shield the element and provide the beans with a travel track B)

www.kitchenkapersdirect.co.uk/images/pP000009779.jpg

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.
 
seedlings
The heatgun elements might be designed with airflow in mind and may fail without it. I don't know for sure, it's just a suspicion.

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

Quote

seedlings wrote:
The heatgun elements might be designed with airflow in mind and may fail without it. I don't know for sure, it's just a suspicion.

CHAD

that was a concern I had too. Plan on hooking it up to the variac will a kill A Watt meter. I thought to go with one of the lower temp. output element thinking this would keep the temp. down. I have a nice sized 1500w nichrome spring element but would have to find some insulating material to wrap it around. Just haven't messed with nichrome much. I may need to run a fairly long spring with low voltage to get a nice radiant ET temp.
I want to do a basic test using the dreamroast and just try a different lid with the element fastened to it. If it could spread 12-1500w out at a non scorching temp. I'd progress with it. It might want a different pot diameter or height.
I've got a 4" wall of beans in a 12"diam. pot that seems could be evenly hit with radiant from a center cylinder shaped element.
But I've got no idea if this can work.
Edited by farmroast on 10/19/2010 12:35 AM
Ed B.
DreamRoast 1kg roaster, Levers, Hand Mills http://coffee-roa...gspot.com/
 
Dan
I own a Master heat gun and a heat blower. The elements for the heat blower are larger. They are about 2.5" in diameter and 5" long, and come in two voltages. I used a 220V unit as a heat source for the drying portion of a mechanized parts washer.

Lack of airflow might cause the element to 'fuse out' if the nichrome gets hot enough to melt.

If you want radiant, then why not go all the way? Use a halogen lamp inside a Pyrex protective cylinder.
 
farmroast

Quote

Dan wrote:
I own a Master heat gun and a heat blower. The elements for the heat blower are larger. They are about 2.5" in diameter and 5" long, and come in two voltages. I used a 220V unit as a heat source for the drying portion of a mechanized parts washer.

Lack of airflow might cause the element to 'fuse out' if the nichrome gets hot enough to melt.

If you want radiant, then why not go all the way? Use a halogen lamp inside a Pyrex protective cylinder.

thanks Dan for the measurement, Yes, I should consider the halogen too.
Ed B.
DreamRoast 1kg roaster, Levers, Hand Mills http://coffee-roa...gspot.com/
 
seedlings
Halogen, of course. Easy, easy, easy to install, control and replace.

Dan A+

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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