Is it a roast issue or a green issue? (Prospective new roasters; you should read this too!) - Page 11

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
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luca (original poster)
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#101: Post by luca (original poster) »

I sort of lost interest in this thread a bit, but remembered about it and figured I ought to post about this.

So I ended up with a fairly mild coffee that had a phenolic defect and thought well I might as well try to deliberately screw up some roasts to create a roast defect kit.

What we learned from tasting this is that the phenolic defect kind of makes bake and flick a little harder to taste, since even if it is under you get a pretty rough finish. So since heaps of commercial roasts, and I'm guessing therefore heaps of home roasts, have bake and flick roast defects, it kind of gave us some additional context as to why people seem so disinterested in the idea that the green coffee they are buying for home roasting may have green defects or be anything other than the finest quality.

The defects all presented as expected, which is to say that under was kind of bland, lacking in aroma and sort of like water with raw oats in it, baked had like a toast type aroma and some additional astringency, perhaps with some softening of acidity, and the flick had a sort of a charred character to the aftertaste. However, I had tried to exaggerate the defects and they were not as intense as I would have liked.

LMWDP #034 | 2011: Q Exam, WBrC #3, Aus Cup Tasting #1 | Insta: @lucacoffeenotes

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#102: Post by mkane »

Our first 200 attempts looked and tasted the same.


#103: Post by GDM528 »

"Phenolic defect" got me searching for ways to detect it at the greens state, and I came across this article: ... 0as%20Rio.

TLDR; shine a UV flashlight on your greens, glowy = bad juju.

I've been trying to navigate a Panamanian Catuai that was prepared with an anerobic slow dry process. So, of course I pointed my UV flashlight at them:

Yikes. *sigh*... These greens would be at home at a rave party.

Is UV inspection useful, or alarmist?

FWIW, this may explain why the ASD greens have punished my attempts to take it below a City+ roast without evoking earthy-sour notes. I checked four other bags of (different origin/processing) greens and observed they all show some level of fluorescence . This has shifted my view to evaluating and roasting greens for both their exploitable attributes and their hopefully conquerable defects.

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#104: Post by yakster »

I believe Thom at Sweet Marias has some information about using UV light to screen his greens. I actually showed him my UV flashlight years ago when I was at an event at their old location.

My experience has been that it's a mixed bag, all that glows is not bad.

LMWDP # 272