coffee roasters

[mars]

Infrared or traditional ? Pros and cons ?

 

[Music_Geek]

Doesn't seem to matter... It changes variables about when you make specific adjustments during roast, but you've had great coffee from both. The IR should be more efficient, from a fuel use perspective, but should respond more slowly.

 

[wwcove]

Generally the main source of heat in all drum roasters is convection. About 70% or more comes from that. Then conduction follows and most roasters actually have a little IR.
The question most ask is drum or fluid and that becomes very ohio acted but most will choose drum for a full body taste.

 

[ellatas]

One could conclude that roasters of all types can produce good roasted coffee since there are many proponents of each out there. However, wwcove is correct in the vast majority of heat transfer is through convection. This means the air has to be heated first and an infrared burner is terrible at heating air. The best it can do is heat the drum exterior and utilize the hot drum to heat the air. Which then becomes difficult to control for profile roasting since you now have a hot drum that is slow to react to different heat demands.
A configuration with an insulated drum (for drum temp stability) and a modulating blue flame burner with a decent turndown ratio (for greater control of the air temp & consequently greater control of the heat transfer to the bean) would provide a roaster with more capability.

 

[CoffeeJunky]

I think you have to think of this way.
Electric car or Gas car.

Why have a car? Because we need transportation.
But why buy electric car? and why should we buy gas car?

If you ask the same questions to people who have been roasting with traditional drum roaster, they would never change to any other method or different type of machine.
Like one of the member stated above, it really doesn't matter. if you get used to the roasting with whatever you have, you can have the same results everytime you roast them.

 

[Music_Geek]

One could conclude that roasters of all types can produce good roasted coffee since there are many proponents of each out there. However, wwcove is correct in the vast majority of heat transfer is through convection. This means the air has to be heated first and an infrared burner is terrible at heating air. The best it can do is heat the drum exterior and utilize the hot drum to heat the air. Which then becomes difficult to control for profile roasting since you now have a hot drum that is slow to react to different heat demands.
A configuration with an insulated drum (for drum temp stability) and a modulating blue flame burner with a decent turndown ratio (for greater control of the air temp & consequently greater control of the heat transfer to the bean) would provide a roaster with more capability.

It stands to reason that unless it's very powerful, the IR burner is going to take longer to heat the drum to saturation, but the physics of the whole thing sort of indicate that if both roasters have solid drums, all that matters is "when you get there." So the trade off on IR vs traditional is time vs fuel. The IR burner is more fuel efficient. If you're going to roast for several hours consecutively, I believe the balance tips in favor of the IR. The slower reaction time just demands some anticipated changes.

In other words, there are extremely talented roasters, roasting on Diedrich because they believe (and have the results to back it up) that the IR tech is the way to go. Likewise, there are extremely talented roasters roasting on old world roasters that would never consider IR burners. In the end, I don't believe anyone can tell the difference in the final product--Someone skilled on both roasters should be able to produce the same results between the two. Changes on either IR or open flame burners are represented with curves, not sharp corners. While there do seem to be points in the roast where a couple of seconds make a difference, MOST of the roast process, that is not the case.

I really think this whole battle matters more to people who drive hybrid cars and build homes out of recycled materials, etc. I think the environmental/economical issue is the only one that merits real consideration... by some folks.

 

[CoffeeJunky]

I am Detroit and first thing it came into my mind is the auto comparison.
Therefore, i have vest knowledge on automotive as well. lol. People always think driving Hybrid or Electric car is environmentally or economically make sense but truth is, IT IS NOT better for the environment to drive hybrid. But that is whole another debatable subject.

So IR and conventional debate is out there but either way, it is personal preference. It would be interesting to do some study on it but as it stands, roasters will always prefer good old drum roaster with burner rather then IR heating unit.

Also if you have ever visited bigger roasting companies, they never really sit there and watching temperature or control each roast. Most of the time, they dump 1000's pounds of beans and let the roaster follow the program. Most of the roasters are busy bagging, destoning, or cleaning the machine rather then watching and tweaking the roaster.

 

[mars]

Thanks everyone