Fluid-bed or Drum?

[Joseph Plaugher]

Hello everyone. I am a pretty new home roaster and brand new to the bx. I am curious what everyone's opinions are about fluid-bed vs drum roasting. I have friends who are hard-core advocates of each, so I want some more opinions. Anyone and everyone, please tell me what you think and why!

[Kyle Fraser]

In my limted experience Joseph, I have found that coffee roasted in a caste iron drum roaster is far more impactful in terms of flavor and aroma than coffee roasted on a fluid bed. I only roast in small batch quantities in drum roasters, as to my own preferences in taste, this is the only method that gets me the aroma and taste that I want.

As a home roaster I would say go for a drum roaster, because fluid-bed roasters were orinally intended for continuous runs and not for batch roasting as they have been used to do in recent years.

Any other information about fluid-bed roasters would be welcome, because although I have seen and purchased coffee roasted on a fluid-bed, I have never done the test of comparison on my own.

[Doug Johnson]

I am a home roaster and have been for the last 8ish years. Started with hot air popcorn popper...quick roast, bright flavor, small batches. I finally built a roaster based on the Stir Crazy from information found starting here
http://www.sweetmarias.com/homemade-homeroasters.php
It appears that Peter Bishop's site that I built mine from is gone now, but the pictures will give you the idea.
A roast takes about 15 plus minutes and results in a mellower coffee (my preference). In addition, I can do 1/2-3/4 pound at a time, so I roast less often (yeah, I know, it's not as fresh, but I'm lazy).

[Joseph Plaugher]

Kenneth Davids says in "Home Coffee Roasting", fluid-bed or hot air roasters (in which the coffee is simultaneously roasted and agitated by a swirling stream of hot air) generally produce a smoother, cleaning cup with less body, while drum roasters produce a more complex, full-bodied cup. I haven't tried roasting in a drum yet. My popcorn machine works well as an air roaster, but I am dissatisfied with the lack of body. I am planning to build a small drum roaster soon. Any other thoughts?

Kyle Fraser said:

In my limted experience Joseph, I have found that coffee roasted in a caste iron drum roaster is far more impactful in terms of flavor and aroma than coffee roasted on a fluid bed. I only roast in small batch quantities in drum roasters, as to my own preferences in taste, this is the only method that gets me the aroma and taste that I want.

As a home roaster I would say go for a drum roaster, because fluid-bed roasters were orinally intended for continuous runs and not for batch roasting as they have been used to do in recent years.

Any other information about fluid-bed roasters would be welcome, because although I have seen and purchased coffee roasted on a fluid-bed, I have never done the test of comparison on my own.

[Joseph Plaugher]

Do you know where to get a cast iron drum roaster?

Kyle Fraser said:

In my limted experience Joseph, I have found that coffee roasted in a caste iron drum roaster is far more impactful in terms of flavor and aroma than coffee roasted on a fluid bed. I only roast in small batch quantities in drum roasters, as to my own preferences in taste, this is the only method that gets me the aroma and taste that I want.

As a home roaster I would say go for a drum roaster, because fluid-bed roasters were orinally intended for continuous runs and not for batch roasting as they have been used to do in recent years.

Any other information about fluid-bed roasters would be welcome, because although I have seen and purchased coffee roasted on a fluid-bed, I have never done the test of comparison on my own.

[Trace Prewitt]

After thirteen years of roasting coffee in a commercial setting AND having read as much literature about coffee as I can I have learned one thing: Kenneth Davids really doesn't know much about coffee or coffee roasting. He is a writer, that's it. I would say that good results can be achieved using any method that applies heat to the coffee over time. Heck you could do it in a fry pan if you bring the temp up properly. Fluid bed or drum or pop corn popper, the problem is the same. You must have maximum control over your heat so you can get about an eleven to thirteen minute roast with a seven to eight minute second pop. finish slowly and you should have drinkable coffee. Problem with a lot of home style roasters is you can't turn the heat up and down. you must be able to control heat and with air roasters, the air speed hitting the coffee.

[Patrick Bock]

It all depends on your taste. But be a roaster for fifteen years I have samples all the coffees at the trade shows and I always find coffee coming for a drum roaster has more body. There is a big argument over cast iron Vs steel. I don't find much difference. A lot of roasters will only use an old probat with a cast iron drum. The only problem I find a lot of new roasters are lacking good burners and don't put out enough BTU's.

I bought a old Dietrich IR 24 and it roasted very bad when I got it, baked the coffee. I switch out the IR burner to a 500,000 power burner and added a bean probe to monitor temperature, it makes great coffee now. Just got to be careful. I have melted some of the metal turning it up to high.

[Bill Sandreuter]

This thread highlights an industry discussion that's been ongoing since Sivetz's fluid bed roasters appeared in the 70's. Trace Prewitt gives visibility to what may be at the heart of the matter - it's the degree of real-time control (manual or programmed) the equipment provides that makes the difference. Drum roaster controls may have gotten a head start (driven by their larger footprint in the industry) over fluid bed roasters in developing sophisticated controls - producing the perception that "drum roasting delivers better body...." and so on. It will be interesting to see if that perception modifies as later generations of fluid bed roasters with more sophisticated control options become available. Even more interesting would be a controlled, fully documented study that controls all variables and directly compares drum v. fluid bed methods...results measured by a panel of experienced cuppers in a blind cupping format. I'd like to hear what people think about this last idea - I'm sure there are some strong opinions out there. :)

[Joseph Plaugher]

Sounds like a cooperative job for some folks from the Roaster's Guild.

Bill Sandreuter said:

This thread highlights an industry discussion that's been ongoing since Sivetz's fluid bed roasters appeared in the 70's. Trace Prewitt gives visibility to what may be at the heart of the matter - it's the degree of real-time control (manual or programmed) the equipment provides that makes the difference. Drum roaster controls may have gotten a head start (driven by their larger footprint in the industry) over fluid bed roasters in developing sophisticated controls - producing the perception that "drum roasting delivers better body...." and so on. It will be interesting to see if that perception modifies as later generations of fluid bed roasters with more sophisticated control options become available. Even more interesting would be a controlled, fully documented study that controls all variables and directly compares drum v. fluid bed methods...results measured by a panel of experienced cuppers in a blind cupping format. I'd like to hear what people think about this last idea - I'm sure there are some strong opinions out there. :)

[Justin Johnson]

Currently fluid beds have zero control over your roast profile built into them. There are a few people out there that are developing new, more versatile fluid beds but I think they are still a few years away. For now the only way to have a personal involvement during the development of the roast is with a drum.

[Joseph Plaugher]

I've heard a lot of negative things about Diedrich roasters. Does anyone have experience with these roasters? Is Probat really better?