Coffee Roasted Twice. - Page 2

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

Failed experiment. Taste like a campfire.

littlenut
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#12: Post by littlenut »

Sorry for late reply, I was trying to sort-out/guess at how-to and how-not-to proceed before you gave it a go, but...

My "thinking" is since you got to 210°C all the water from first crack would have been released and evaporated. I would have guessed at a given heat transfer rate you would get a bigger temperature differential between surface and center while reroasting these beans. My GUESS would be reheat slower than usual so exterior temp doesn't get too high. Then when you "feel" it is up to where your first dumped the beans to proceed as you normally would.

Anyway FWIW this morning's Panama Gesha was tasty....

Trjelenc
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#13: Post by Trjelenc replying to littlenut »

In coffee roasting, I always see the discussion around water content creating density and thus effective heat transport, but I never ever hear anyone talk about the specific heat of water. While the density allows heat to travel within the bean easier, there's an opposing act of water absorbing more energy for each ° temp increase than the rest of the bean structure. In other words, a higher water content means your heat application doesn't go as far in terms of increasing the beans temperature.

littlenut
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#14: Post by littlenut »

Sorry trying to think this through hurt my head....gonna thunk a li'l

Trjelenc
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#15: Post by Trjelenc »

Coffee roasting is friggin complicated man. Theorizing the potential thermodynamic cause and effect that makes a roast go a certain way is really fun, but I typically tune out people who overzealously reach into scientific explanations to sell you their prescribed roasting approach as the Universal Truth™, in a "it's not an opinion, it's science" type way. There's a certain very influential consultant who I think dips his toes in this realm a lot :wink:

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mkane (original poster)
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#16: Post by mkane (original poster) »

I personally like the numbers approach. Without em' where do you start?

If I had numbers in the beginning, it would have saved me lots of $$$$ spent on green coffee.

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