Roasting techniques to emphasize the coffee's origin

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
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Kuban111

Postby Kuban111 » Apr 25, 2007, 9:58 am

Hola Jim, :D

From Roast Length for Aged & Monsooned:

another_jim wrote:Drawing out the time from 300 to first crack isn't so brilliant, since it will accentuate the woody flavors. Where drawing out pays out with these is after the first crack (above 390 to 400 bean temp). This will lower the environmental temperatures and lower the second crack temperatures. You want to go to a rolling second for these.



Sorry I hope I'm not taking things out of context. But what you said caught my attention.

I just finish roasting a Costa Rican and an Italian/French blend this pass weekend on my UFO/TO combo.

What I normally have been trying to follow is preheat the UFO/TO combo at 350.f , drop the beans and hold it there for 5 min. then take it to 500f ramping up slowly till it gets to 500f. I leave it there for 1st crack and until I decide to stop the roast.

But this past weekend I roasted out side (82.f), pre-heated 350.f
I started at 230.f. ramped up super slowly from 230.f it took 11 min to get to 1st crack ambient temp inside was 496f.
2nd crack came around 6min after. Then I left it there until a little after 2nd crack but not all the way thru until I stopped. Total roast time was 17 min.

What did I notice?
° The bean color on both roasts that I took to 2nd crack didn't have the normal deep dark brown color that I was getting before. Instead it looked to have a more brown earthy type tone.
° No oil on the surface of the beans (normally some or very oily)
° Didn't have a deep dark aroma but again a more subtle nuttier woody smell.

The coffee tasted great. Both French press and as espresso.

Your description on that statement sounded like what I ended up with.

So did this happened b/c I took a longer time to reach 1st crack than normally?

Or would it be a better idea to get to 1st crack at a shorter time then stretch out 1st crack a lot longer before it gets to hit 2nd crack. Then stop the roast.

What I'm trying to achieve would be to learn how to emphasize the origin of the beans at this moment. Would you have any suggestions on how I can start to achieve this goal?

Thank you, for your help & sharing your knowledge.
Plus the time & patience it takes to answer our newbie questions.

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another_jim
Team HB

Postby another_jim » Apr 25, 2007, 11:51 pm

My current "roasting theory" is to divide the roast into 3 phases based on the temperature of the beans (or a reasonable substitute). I think this is sound, but there's no guarantee that it'll hold up in the long run.

Drop-in to about 300F: In this portion the beans aren't roasting, instead they are drying and warming up to an even temperature. A minimum of 4 minutes is required here to get the beans warmed to the center. Less than that, and the centers stay cool and wet, and one gets grassiness in light roasts. One needs to go longer if the beans are very fresh or moist. The idea is that the beans are uniformly yellow (not tan or green) by the time they go past this mark.

300F to 1st crack start: During this part of the roasts, the acids are chemically stable, but sugar and protein are being combined into Maillard compounds -- these have woody, nutty, malty, bready, toasty flavors. The sugars used to produce these flavors are subtracted from the sweetness of the coffee. For this reason I like to keep this segment short, however, if a coffee is very sweet, and the flavors developing here are very fine (say almonds and cognac barrel oak) by all means linger. If the woody and nutty flavors in the coffee suck, go as fast as you can.

1st Crack to Roast End: In this phase the sugars caramelize and the acids degrade. You need to spend some during the first crack degrading the chlorogenic acids, otherwise the coffee will taste acrid-bitter, green, and vaguely like an overchlorinated swimming pool. If you like low acidity and light caramels, roast slow and end while the beans are still light. If you like smokey flavors with a touch of crispness left, roast dark, but get there fast. In generel, it pays to finish dark roasts as fast or faster than light roasts by speeding up the roast at this point when going dark, or slowing it down when staying light. One exception to this is cupping roasts, where you want to end soon after the first crack to preserve all the distinguishing origin flavors. However, when doing this, brew the coffee (never espresso) and use a lower coffee to water ratio. The other exception is low acid coffees like Sumatra or some Brazils, where roasting dark slowly can prevent the coffee from becoming ashy.

I'm not sure if this answers your question about origin specific profiles. Brazils and Sumatras take slower profiles in many cases; but for most other coffees, I do a standard roast, than add or subtract time from each section according to taste the sections to taste.
Jim Schulman

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Kuban111

Postby Kuban111 » Apr 26, 2007, 8:35 am

Thanks Jim,
Yes is does and much more like always to digest,

There's a lot of homework and fun to enjoy in what you wrote.

It comes at a great time; my wife is going on a business trip to Chile and Brazil.
I'll have a lot of time on my hands and I was planning on getting a 5lb bag of Mexican greens and spending it roasting.

On a side note:
Those any one know, what the policies of bringing roasted or un roasted coffee bean in to the country are.

Thanks again.

DaveC

Postby DaveC » May 14, 2007, 5:45 pm

To preserve origin quality as a generalisation try:

When bringing the coffee to 1st crack, apply enough heat to ensure 1st crack is going nicely...but no more heat than you need to do that. In fact you can lower the heat input when the beans are some way into 1st, but depending on the roaster and heating method, will determine how much and when you can reduce it. your objective would be to try and achieve sufficient heat for 1st to go nicely and then have the time temperature curve flatten off.

Try not to take the beans too far into 2nd crack (this of course depends on bean), some you may want just near 2nd but not into it, a roasting log is a real life saver here.

Don't "bake the beans", roasting too long at too low a temperature, may give a nice even roast, but does nothing for taste. Certain beans will look uneven (dry processed ethiopians), but don't worry too much about it...however worry if a dry processed ethiopian comes out really even....chances are it will taste bland and baked. Enough heat but not too much.

Be mindful of the type of processing, bean hardness, size and humidity etc.. that will affect the roast.

e.g. A SHB (Hard bean) an be pushed along with quite a steep temp profile and higher temps, a softer bean will not respond well to this sort of abuse. One coffee might like a higher temp and have longer roast times than another e.g. Colombian vs Lekempti (two very different roast characteristics)

Lastly research your beans, share roasting logs and keep roasting logs.

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cpl593h

Postby cpl593h » May 14, 2007, 8:55 pm

At/after first crack, do you believe there is a minimum temperature increase per minute?

DaveC

Postby DaveC » replying to cpl593h » May 14, 2007, 9:10 pm

Cant really answer that, depends on bean, roaster, how the roasts going and other factors

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cpl593h

Postby cpl593h » May 14, 2007, 9:15 pm

Of course. I've always wondered if there is a theoretical minimum rate of progression, and I've never tried it myself. Might as well...

DaveC

Postby DaveC » replying to cpl593h » May 15, 2007, 10:47 am

Ah I see.....a bit tounge in cheek (but many a true word said in Jest) let the basic Hottop roasting in Winter outside be your guide :lol:

The theoretical minimum rate of progression might best be thought about as anything giving you a 17min+ 1st crack time, other than that it's really down to the coffee (type, %water etc..). Trouble is your not comparing apples with apples. The temperature sensors and heating methods mean that all roaster show this differently, even two roasters that are the same make and model, won't necessarily measure the temperature the same. Take a roaster that heats predominantly by IR, this type of heat penetrates the bean better than say conduction, and will hence give completely different roast characteristics for a given overall temperature and rate of temperature increase. In my Toper I bean drop at 185 with a max temp of 195, in a 25Kg gas fired probat I might drop at 160 and have a max of 235C.....the readings don't really mean anything, neither does the indicated rate of progression, because of the different heating methods.