Development time as a ratio of roast time by Scott Rao - Page 2

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

Wouldn't the sugars have to be considered in relation to time back around 365f +-, isn't that where the sugars start cooking/melting point? Where for chlorogenic acids it's around 405f
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another_jim
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#12: Post by another_jim replying to farmroast »

Then you'd want to rush to the first crack to spare the sugars, cut the heat, and slow it down afterwards to reduce the chlorogenic acids.

Now where have I heard that before? Isn't that the old prescientific, pre third wave, pre-ratiometirc, dark ages way of roasting?
Jim Schulman

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farmroast (original poster)
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#13: Post by farmroast (original poster) »

Crack profiling, speeds in and out when light roasting seem more the issue. The rest as Jim replied is same as it ever was. Still consider development for reference between clean sweetness to caramel goodness
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ripcityman
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#14: Post by ripcityman »

Tom, Rich, Jim

Amazing thread. Thank you gentlemen, I am not worthy.

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TomC
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#15: Post by TomC »

I think Songer's graph sums it up pretty well.
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Mile High Roaster
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#16: Post by Mile High Roaster »

I would think that a shorter profile might often require more development time after first crack rather than less, as Mr. Rao suggests. Otherwise the seed might not get roasted enough. But even that said, there's no accounting for taste.

This seems like a particular roasting style disguised as a rule of thumb.

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endlesscycles
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#17: Post by endlesscycles »

Mile High Roaster wrote:This seems like a particular roasting style disguised as a rule of thumb.
I agree. I would think 25% is unavoidably baked. Also, many Nordic roasters have numbers below 15% whose coffee is well received around the world.
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boar_d_laze
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#18: Post by boar_d_laze »

Mile High Roaster wrote:This seems like a particular roasting style disguised as a rule of thumb.
endlesscycles wrote:I agree. I would think 25% is unavoidably baked. Also, many Nordic roasters have numbers below 15% whose coffee is well received around the world.
The Rao article lacks context. It makes no sense talking about percentage of total roasting time for Development without consideration of the coffee's ultimate finish level. A roast finishing at a Nordic, barely out of 1stC will and should have a much lower proportion of Develpment than one finishing at FC (much less FC+), even if the roast master distorts the roast by dragging the 1stC period then rushing the rest of the way through Development.

It might also be important context to consider about the bean being roasted. Maybe. Possibly.

And not to beat a dead horse any more (can we get a fresh dead horse in here?), but you really have to look at ALL the intervals within the profile. It's all very talking about an ideal Development, as though it stood alone on a pedestal. The best Development is contingent; very much dependent on the preceding execution of Drying and Ramp. Intervals are a convenient way of talking about roast progress, but they don't actually exist in isolation.

Rich
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TomC
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#19: Post by TomC »

another_jim wrote:The decrease of chlorogenic acids also happens roughly above 390F; and decreasing these is vital to getting roasts that don't taste raw, rough, acidic and bitter. If one could know the precise rate of decay of sugars and chlorogenic acids as one gets into the 1st crack, one could stall the roast at temperatures where the decay of chlorogenic acids is fastest, and speed up where the decay of sugars is fastest. This would be the most scientific way of getting the most perceptually sweet light roasts.

I've roasted a long time, and have no sense of how these sugar versus chlorogenic decay rates respond to temperature. It would take precise and long winded experimentation to work out.


At some point, there'll be enough curiosity for sampled exhaust gas to be attempted. The industry would need to find someone who's good friends with a very large lab though. If we knew the cut off point at which chlorogenic acid decay starts to decline in the exhausted air, we'd be able to stop a roast or alter path rather quickly.

Even more interesting would be to standardize a few common profiles, pay less focus on temps or even visual bean development in this instance, and just have the (chromatography?) gas analysis captured and see what's happening during all stages of the roast.

I think you can set all the science aside and train a monkey practically, anyone with a decent sense of smell and capacity for attentiveness, and make great roasters out of them by just using sensory input and precise thermometry to roast coffee. Scott Rao and the like can continue to write books about pet theories. But short of something beyond his broad and unproven ideas, I don't know what he's adding to the greater context of the conversation. What did he say specifically, that can be proven, that "improves" roasting.

I wish I could sneak home one of our NICO devices from the ICU, I could trend CO2 in about 2 dozen ways. It wouldn't take much more than some duct tape to splice in and analyze exhaust gasses. I imagine it would be quite fascinating, but one phenomena likely wouldn't correlate with a given value, i.e., the cockcrow doesn't make the sun rise....
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DavidMLewis
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#20: Post by DavidMLewis »

To be fair to Scott, he never presents what he is saying as anything other than an observation, and further qualifies it with this:

"To be fair, I don't often cup roasts dropped well before the end of first crack or well after the onset of second crack, so I won't assume the ratio is valid for those roast levels."

As often happens, the qualifiers get dropped as you move away from the primary source.

Best,
David