Scott Rao on The Flick

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
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yakster

Postby yakster » Aug 18, 2015, 5:58 pm

New blog post on Cropster by Scott Rao on The Flick--increase in ROR, flick up in the graph, following first crack--and it's effect on the coffee. It's geared towards using Cropster to monitor the roast, but general enough to be useful to anyone monitoring ROR during the roast.

https://www.cropster.com/news-detail/the-flick/

(updated link, works again now)
-Chris

LMWDP # 272

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Stereo Heathen

Postby Stereo Heathen » Aug 19, 2015, 2:54 am

Thanks for the link.

He really doesn't say anything new here, does he?

edtbjon

Postby edtbjon » Aug 19, 2015, 4:33 am

Well, there are (possibly) some new pieces of facts in there. I really don't remember him being that focused on this small but important part of the roast in the book. As far as my memory goes (not far... :) ) he talks about this phenomena in a few sentences. In this (new) article there's about a full (maybe just a bit short) chapter on this very subject. I think I'm gonna print it out and put it in the book...

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Stereo Heathen

Postby Stereo Heathen » Aug 19, 2015, 11:52 am

Right! Absolutely. I should have said "he really doesn't say anything different", given that it's one of the same points with more emphasis.

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JavaMD

Postby JavaMD » Aug 19, 2015, 4:31 pm

I'm intrigued by the promise of "how to handle" the first crack exothermic drop. can't wait for that discussion.

steve

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farmroast

Postby farmroast » replying to JavaMD » Aug 19, 2015, 5:27 pm

I don't play with drum roasters much and of course it depends a lot on the specific roasters design. But in general it would seem that if a heavy drum has too much stored energy during 1st crack that can't be dissipated during the first part of 1st it will be hard to avoid a flick towards the end of 1st. If it's possible to use up excess stored energy in drum as approaching 1st and then drive more with heated air/convection that can usually be adjusted more quickly you can then have more control at flick time.
LMWDP #167 "with coffee we create with wine we celebrate"

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Boldjava

Postby Boldjava » Aug 19, 2015, 5:53 pm

I will be the 1st to admit that I am still working on eliminating the flick. Thought Scott would have more definitive ways of driving the roast (BTUs, air, drum speed) at control points. I find it a perplexing quirk that defies my management. Still get good coffee but would love to eliminate it.

Color me flicked...
-----
LMWDP #339

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Andy

Postby Andy » Aug 19, 2015, 8:11 pm

Does anyone have any thoughts about how the related issues of declining RoR and The Flick and its consequences might pertain -- or not -- to fluid bed (ie. popper) roasting? I have been thinking this is a thing drum roasters have to deal with, but I just looked at a random few of my profiles and sure enough, most of them have a slight rise in RoR during 1C.

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Randy G.

Postby Randy G. » Aug 19, 2015, 8:24 pm

My OPINION would be that the beans know little of where the thermal energy is coming from. One way to find out though is to complete a roast without the Flick and do a taste test. I assume that you have separated the heat and fan for control, so it should not be too difficult to do.
Image
This is the last roast I did.I hit the Start of 2nd a bit early so it didn't actually last as long as it shows. I would have to check my control alarms to be exact, but at about the 11½ minute mark the fan was at 100% and the heat was, at the most, 10%. You can see how the ET flattens then drops off at the end. Now to get rid of the hump at 7:00 to 7:45.
Espresso! My Espresso!
http://www.EspressoMyEspresso.com

treq10

Postby treq10 » Aug 20, 2015, 2:20 am

I've come to believe that the problem of the flick is a very simple one: the time it takes for the inner bean to be cooked throughly up to the desired temperature before over roasting the outer bean.

This is why a decreasing RoR is so important. It slows down the roast enough that the inside can catch up with the outside without over roasting the outside. It's the art and craft of the roaster to accomplish this without roasting too long as to bake out the acids and sugars.