Watched 44 lbs of Kona roasted in 10 minutes at over 500 degrees!

[bigislandbeans]

I'm holidaying and attending the Kona coffee festival on the Big Island. I visited a farm and watched them do a roast with a fluid bed roaster. 44 lbs was roasted to a full city + in ten minutes. They dropped the beans at somewhere around 513 degrees. They claim the roasts in their drum roaster take about as long. I thought fluid bed roasters were faster than a drum.
Does that seem excessively fast for a roast and a really high temp for Kona beans?

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[topher]

Its been a while since I have played with a fluid bed roaster. I remember it being faster than a drum...but the temps you mentioned seemed high. What temp did they start off at? It does seem quick and the temp seems high...but the truth is in the cup. Did you happen to taste their coffee?

[bigislandbeans]

I didn't see the temp that they started the roast at as I arrived at about 5 minutes into the roast, but even at that point it was 450 and above in temp.
I did taste their coffee in the sample room and while it was a little darker than I would like it was quite good.
I don't know if it was fluid or drum roasted.

[topher]

Is it just me or does anyone else think their probes might be off? 450 degrees 5 minutes in seems way high...did you see the beans after the roast? Did they scorch or were they tipped? I wish I could watch the process there....

[DirtyDave]

I think there is some degree of incomplete information here.
I know of no air roaster that pre-heats their roast chamber (drop temp for you drum guys).
One of the advantages of air roasting is that you can actually measure the temperature that
the beans are subjected to.
44 lbs isn't a whole lot of beans, so having an inlet air temp of 450 degs F doesn't seem untoward (@ 5 mins in).
Kona beans to full city +; ack, not my style.
That roaster cannot profile, it is a passive, random spouting bed roaster (not truly fluid bed).
Having said that, I am an avowed air roasting fan, just not the passive uncontrolled kind.

[DirtyDave]

The 500 degs F indication you saw was most likely the pressurized hot air inlet stream temp.
500 degs F doesn't = coffee, it = charcoal.

[topher]

dave...I was asking about drop temp in their drum roaster. He mentioned that the times and temps were about the same in their drum roaster. I'm with you on the full city+ roast for Kona..

[bigislandbeans]

Ya, sorry guys, I can't give you all the info as we walked in half way through the roast. The make of the roaster was a sivetz.
It seems that all of the coffee I've tasted here other than what was in the cupping competition is all roasted to a city + at least, no oil on the bean just darker than a medium. And I have to say, all of my customers buying Kona want it that way and no lighter. And looking at the beans in my bag of Greenwell's private reserve, it's at the same roast. It tastes excellent.

[CJevens]

I was just in Kona for 5 weeks and worked on a couple farms. (Pele Plantations and Dragons Lair) I did roasting on Sivetz and never saw temps over 450 as measured by a probe through the side of the bean chamber into the mass of moving beans. Anything much over 450 was getting into Dark territory quickly with risk of fire and charcoal.

I would question the accuracy of the thermocouple being used and its placement. 500*F sounds like charcoal. I agree.


What farm were you visiting? NO plug for the farm ?

Greenwell is a very influential and respected farm in the region. Tommy Greenwell is very active in the community.

[DirtyDave]

Coffee is regularly roasted (in Sivetz style roasters) to over 470 degs F with no risk of fire.
That may not be to your taste, but as long as the bean bed has vigorous agitation, you don't have to worry about fire.
Of course, all these "fluid bed" roasters are passive devices, with little or no control over the profile, you get what you get.
With some creativity (and $) you can transform a "fluid bed" roaster into an all singing, all dancing, easily controlled and changable, profiling delight (roasting the coffee at reduced heat transfer levels, thereby preserving elements of flavor and aromatics).