Interesting professional roasters' discussion - Page 2

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

#11: Post by John P »

Jim,

when roasting Pacamara, charge your drum at 215-225F, and have a more gradual roast--about 6 degrees per minute on your bean temp-- until you hit first crack (375... give or take a few degrees) increase to about 9-10 degrees per minute (bean temp) after hitting first crack... level out your temp after about two minutes ....and you should finish in about 30 seconds to 1 1/2 minutes max after that.

Pacamara and Margogype are not as dense as your typical SHB and if you roast at the same rate as your typical roast the inside of the bean will overheat. This will kill a lot of the flavors.
John Piquet
Salt Lake City, UT
caffedbolla.com

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another_jim
Team HB

#12: Post by another_jim »

Thanks, an "ultra-drum," slow start, fast finish roast. I'll give this a try.
Jim Schulman

jason_casale

#13: Post by jason_casale »

Jim,
this is interesting information about half of it I all ready knew.
I understand that polyphenols are breaking down in the stage before 300 as well as moisture.
My profile for the verona espresso that you have tried used this type of profile.

Turn around at 200 degrees 1:30 seconds into roast. 250 at 4 minutes.
300 at 7 to 8 minutes. 1st crack 370 375 at 11 to 12 minutes before reaching 1st crack I dropped the heat to low at 365 about 30 seconds to a minute before 1st crack would begin.
I would leave it on low for another 2 minutes until 1st crack would finish.
This would produce a slow controlled 1st crack that usually would not go above 400.
The gas would be on low a total of 2:30 to 3 minutes a little before 1st crack all the way thru first crack.
This technically would be referring to the Italian style of roast slowing down the roast to stretch out the sugar chain as much as possible.
I have found that most controlled 1st cracks take a total of 2 minutes from start to finish.
If you leave the gas on low past 1st crack you start to lose bean temp heat and stall the roast baking the coffee.
At the end of 1st crack I was some where in the 400 degree range.
14 to 15 minutes in roast at this point.
I would slowly bump the heat in increments 1/4 turn up on the gas wait 1 minute then a quarter turn up on the gas every 30 seconds for not more than 1 1 minute interval and 3 30 second intervals. (Medium to medium high heat on the roaster)
This put me at 425 430 a little past the beginning of second crack roast end.
medium roast dry beans out of the roaster.
Second crack would begin at 415 420 or so.
The reason for the slow bump on the heat at the end was 2 fold for me.
I wanted to mellow out the acidity quit a bit for northern italian espresso.
Second If I ramped up the heat to fast in the end of the roast sometimes I would get scorching tipping.
A note about 1st crack and second crack if your heat is to aggressive in either stage you to have very loud fast hard cracking that can cause what are known as blow holes or divots.
The other reason for the slow controlled heat bump right before second crack.

Most people who tried my verona blend where amazed that such a light roast had that much body and was not astringently sour but very balanced. This was accomplished using the temp drop before 1st crack and thru 1st and controlled temp slow ramp up after 1st thru second to roast end.

I would generally use this same theory for other coffees sometimes just quicker for strictly hard bean. 9 minute 1st crack 10 minute 1st crack for medium soft beans 11 to 12 minute 1st for espresso or soft bean.
generally it would work very well. I read alot about roast techniques from willem boots ruling the roast articles all very good.

Thank you Thank you for putting this information together it will greatly continue to help me as I continue to roast everyday on our companies diedrich ir3 a complete time temp profile roaster which I love.
Thanks Jason

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John P

#14: Post by John P »

Jim,

yes... your breakdown on the roasting process is simple and to the point.
A wealth of information hidden inside there.
John Piquet
Salt Lake City, UT
caffedbolla.com

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another_jim
Team HB

#15: Post by another_jim »

Thanks, but this information is readily available in the literature, and fairly easily confirmed in its rough outlines.

I don't think there's enough to tell you how to roast a specific bean up front, but it might reduce the number of roasts needed to get to the best profile.
Jim Schulman

Viridian

#16: Post by Viridian »

I think that it is kind of funny that Bear, in the article referenced in the first post, refers to a set of experiments that Jeffrey Pawlan conducted. I remember that and have written to Jeffrey to ask him about the results of those experiments. He assured me that when he had worked his way through the sheaf of results he would publish his findings.

"Dear Erik,

I carried two huge binders of data weighing about 30lbs around the SCAA
conference showing it to various people. I had done some statistical analysis
and graphing of this. Then I had a couple of meetings with the statistician who
was helping me in his spare time. He wants to change the method of analysis. I
must wait for him to be available. When we are done, it will be published.

Regards,
Jeffrey Pawlan"

http://www.pawlan.com/RoastProfileResearchSession2.html

I don't doubt that he is a very busy man.

Viridian

#17: Post by Viridian »

another_jim wrote:Thanks, but this information is readily available in the literature, and fairly easily confirmed in its rough outlines.

I don't think there's enough to tell you how to roast a specific bean up front, but it might reduce the number of roasts needed to get to the best profile.
Hi Jim,
Might I ask what literature? I think it is time I delved into it. Would Illy's book be a good place to start?

Thanks!
Erik

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another_jim
Team HB

#18: Post by another_jim »

The chapter in Illy is hard going, but has some good stuff. Clarke and Vitzthum's edited volume explains the 1990s switchover by the large roasters from fast 3 minute to more craft roast like 8 to 10 minute ones. The best intro I've found is Schenker's roasting dissertation. The full dissertation is 26megs, so it's best to save the PDF locally.
Jim Schulman

Viridian

#19: Post by Viridian »

Thanks Jim, I'll do my best to wade through it.

Frost

#20: Post by Frost »

Thank you Jim for all the knowledge and information you bring on this subject. I've been working through the Schenker paper. Plenty to sort and study, but I am most perplexed why he choose to do his lab roasts (HTST,LTLT) as Isothermic roasts. I'm guessing he was not a 'home roaster' at the time or he would have developed more 'empirically optimized temperature/time profiles' as is done in commercial/industrial roasting. I think this is unfortunate, but there is still alot of good work here.