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Date: 31 Oct 2006 11:48:37
From: DavidMLewis
Subject: early roast profile affects 2nd crack temp
I've seen something roasting the Hache Co-Op Sidamo that I don't
understand. I now have the ability to profile roasts fairly repeatably.
If I run the segment from 265 F to 295 F over 1'30", I hit 2nd crack at
440 F, which is a usual temperature for me to see it. If, though, I
take 2'30" for the early ramp, I don't see 2nd until 453 or so. 1st
crack doesn't seem to move, occurring at around 404 in both cases.
Ideas?

David





 
Date: 02 Nov 2006 09:50:13
From: Erik Groomer
Subject: Re: early roast profile affects 2nd crack temp
I'll buy that. I AM interested though to hear what you have found with
regards to your profile experimentation, ie: your drying phase
profiling. Care to share?

Erik

Jeffrey Pawlan wrote:
> Erik Groomer wrote:
> > I have also been playing with the drying phase and am flummoxed by the
> > change in temp for 1st and 2nd. When roasting 6lbs I have had 1st hit
> > as much as 20degF higher and 2nd hit 10degF higher.
> >
> > Erik
> >
>
> I think the best empirical approach will be the Outcome of the roast. In
> other words, let's not worry about the temperatures of the cracks or
> even whether there IS a 2nd crack at all. Instead, let us together find
> the best roast profiles for different origins and different bean prep
> methods.
>
> Regards,
>
> Jeffrey Pawlan



  
Date: 04 Nov 2006 02:49:57
From: Jeffrey Pawlan
Subject: Re: early roast profile affects 2nd crack temp
Erik Groomer wrote:
> I'll buy that. I AM interested though to hear what you have found with
> regards to your profile experimentation, ie: your drying phase

I posted the majority of what I have found so far. it is not detailed
and is not bean specific.

The research session that we did on Oct 22 could only accomodate 9
roasts due to restricted time and resources. It has resulted in quite a
few scoring sheets which I must now analyze. The task is so large that I
am currently writing a program to first enter all the data in to a
database. Then I will write programs to do many forms of analyses.


Regards,

Jeffrey Pawlan



   
Date: 04 Nov 2006 19:10:52
From: I->Ian
Subject: Re: early roast profile affects 2nd crack temp
On Sat, 04 Nov 2006 02:49:57 GMT, Jeffrey Pawlan
<devnull@sbcglobal.net > wrote:

>
>I posted the majority of what I have found so far. it is not detailed
>and is not bean specific.

Posted Where under Topic?


 
Date: 02 Nov 2006 06:25:09
From: Erik Groomer
Subject: Re: early roast profile affects 2nd crack temp
I have also been playing with the drying phase and am flummoxed by the
change in temp for 1st and 2nd. When roasting 6lbs I have had 1st hit
as much as 20degF higher and 2nd hit 10degF higher.

Erik

DavidMLewis wrote:
> I've seen something roasting the Hache Co-Op Sidamo that I don't
> understand. I now have the ability to profile roasts fairly repeatably.
> If I run the segment from 265 F to 295 F over 1'30", I hit 2nd crack at
> 440 F, which is a usual temperature for me to see it. If, though, I
> take 2'30" for the early ramp, I don't see 2nd until 453 or so. 1st
> crack doesn't seem to move, occurring at around 404 in both cases.
> Ideas?
>
> David



  
Date: 02 Nov 2006 16:31:27
From: Jeffrey Pawlan
Subject: Re: early roast profile affects 2nd crack temp
Erik Groomer wrote:
> I have also been playing with the drying phase and am flummoxed by the
> change in temp for 1st and 2nd. When roasting 6lbs I have had 1st hit
> as much as 20degF higher and 2nd hit 10degF higher.
>
> Erik
>

I think the best empirical approach will be the Outcome of the roast. In
other words, let's not worry about the temperatures of the cracks or
even whether there IS a 2nd crack at all. Instead, let us together find
the best roast profiles for different origins and different bean prep
methods.

Regards,

Jeffrey Pawlan



 
Date: 01 Nov 2006 03:46:28
From: JulesG
Subject: Re: early roast profile affects 2nd crack temp
Very interesting thread. I learn a lot from you guys. Thanks for
sharing this info.



 
Date: 31 Oct 2006 15:23:52
From: DavidMLewis
Subject: Re: early roast profile affects 2nd crack temp

I- >Ian wrote:
> On 31 Oct 2006 13:33:32 -0800, "DavidMLewis" <DavidMLewis@mac.com>
> wrote:
>
> >
> >I->Ian wrote:
> >> On 31 Oct 2006 12:09:12 -0800, "DavidMLewis" <DavidMLewis@mac.com>
> >> wrote:
> >>
> >> >
> >> >I->Ian wrote:
> >> >> On 31 Oct 2006 11:48:37 -0800, "DavidMLewis" <DavidMLewis@mac.com>
> >> >> wrote:
> >> >>
> >> >> >I've seen something roasting the Hache Co-Op Sidamo that I don't
> >> >> >understand. I now have the ability to profile roasts fairly repeatably.
> >> >> >If I run the segment from 265 F to 295 F over 1'30", I hit 2nd crack at
> >> >> >440 F, which is a usual temperature for me to see it. If, though, I
> >> >> >take 2'30" for the early ramp, I don't see 2nd until 453 or so. 1st
> >> >> >crack doesn't seem to move, occurring at around 404 in both cases.
> >> >> >Ideas?
> >> >> >
> >> Do the beans look the same in the two roasts at 2nd crack?
> >
> >No, they're less even if the early part of the profile is shorter.
> >
> What about size?
>
> And smoothness of the outside of the bean?
>
> Assuming the same start weight, what are a the finished roast weights?

All good questions, which will have to wait until next week to answer;
I'm going to a family wedding this weekend.

David



 
Date: 31 Oct 2006 13:33:32
From: DavidMLewis
Subject: Re: early roast profile affects 2nd crack temp

I- >Ian wrote:
> On 31 Oct 2006 12:09:12 -0800, "DavidMLewis" <DavidMLewis@mac.com>
> wrote:
>
> >
> >I->Ian wrote:
> >> On 31 Oct 2006 11:48:37 -0800, "DavidMLewis" <DavidMLewis@mac.com>
> >> wrote:
> >>
> >> >I've seen something roasting the Hache Co-Op Sidamo that I don't
> >> >understand. I now have the ability to profile roasts fairly repeatably.
> >> >If I run the segment from 265 F to 295 F over 1'30", I hit 2nd crack at
> >> >440 F, which is a usual temperature for me to see it. If, though, I
> >> >take 2'30" for the early ramp, I don't see 2nd until 453 or so. 1st
> >> >crack doesn't seem to move, occurring at around 404 in both cases.
> >> >Ideas?
> >> >
> Do the beans look the same in the two roasts at 2nd crack?

No, they're less even if the early part of the profile is shorter.

David



  
Date: 31 Oct 2006 21:50:18
From: I->Ian
Subject: Re: early roast profile affects 2nd crack temp
On 31 Oct 2006 13:33:32 -0800, "DavidMLewis" <DavidMLewis@mac.com >
wrote:

>
>I->Ian wrote:
>> On 31 Oct 2006 12:09:12 -0800, "DavidMLewis" <DavidMLewis@mac.com>
>> wrote:
>>
>> >
>> >I->Ian wrote:
>> >> On 31 Oct 2006 11:48:37 -0800, "DavidMLewis" <DavidMLewis@mac.com>
>> >> wrote:
>> >>
>> >> >I've seen something roasting the Hache Co-Op Sidamo that I don't
>> >> >understand. I now have the ability to profile roasts fairly repeatably.
>> >> >If I run the segment from 265 F to 295 F over 1'30", I hit 2nd crack at
>> >> >440 F, which is a usual temperature for me to see it. If, though, I
>> >> >take 2'30" for the early ramp, I don't see 2nd until 453 or so. 1st
>> >> >crack doesn't seem to move, occurring at around 404 in both cases.
>> >> >Ideas?
>> >> >
>> Do the beans look the same in the two roasts at 2nd crack?
>
>No, they're less even if the early part of the profile is shorter.
>
> David

What about size?

And smoothness of the outside of the bean?

Assuming the same start weight, what are a the finished roast weights?


 
Date: 31 Oct 2006 15:32:02
From: jim schulman
Subject: Re: early roast profile affects 2nd crack temp
On 31 Oct 2006 11:48:37 -0800, "DavidMLewis" <DavidMLewis@mac.com >
wrote:

>I've seen something roasting the Hache Co-Op Sidamo that I don't
>understand. I now have the ability to profile roasts fairly repeatably.
>If I run the segment from 265 F to 295 F over 1'30", I hit 2nd crack at
>440 F, which is a usual temperature for me to see it. If, though, I
>take 2'30" for the early ramp, I don't see 2nd until 453 or so. 1st
>crack doesn't seem to move, occurring at around 404 in both cases.
>Ideas?
>

I find it odd and interesting. My experience has been that extending
this warmup period leads to a hotter first crack and cooler second
temperature.

So I have no idea what's happening here, and look forward to hearing
more.


  
Date: 31 Oct 2006 22:36:59
From: Jeffrey Pawlan
Subject: Re: early roast profile affects 2nd crack temp
jim schulman wrote:

> I find it odd and interesting. My experience has been that extending
> this warmup period leads to a hotter first crack and cooler second
> temperature.
>
> So I have no idea what's happening here, and look forward to hearing
> more.


David and Jim,

I have been experimenting with variations in the first part of the
roast profile which I call the drying or dessicating phase. There are
more experiments to do but so far I can tell you the following observations:

1. The drying or dessicating phase is VERY beneficial to the coffee
flavor, but.... if too long it actually will ruin (reduce the flavors)
in an otherwise excellent bean.

2. Too short and the result is basically what you (Jim) and others may
have perceived with an air roaster: very bright, acidic, often
accompanied by grassy underdeveloped notes.

3. Since David and I have the ability to duplicate each other's roasts
almost exactly, we can try some experiments in parallel. My latest one
is a single roast of a Sulawesi Toraja from Coffeewholesalers and I
intentionally set my controller to turn the heater on 100% from the time
the beans were in until the bean mass reached 225 deg F. This noticably
shortened the time from 5 min to 3 min. I then continued the drying
phase for a couple of minutes (sorry my profile is not on this computer)
and then went into the roast segment. If I remember correctly, I
manually stopped the roast well into 2nd crack at 442 deg F. The roast
appears to be FC+ with not a spot of oil even after several days. Under
my stereo microscope I can see some faint tipping on the beans, probably
because of the intense radiant heat going through the perforated drum.

I made several double espressos after 1 and also 2 days rest and 3 of
them were sublime. Some of you may say godshots. I was greatly surprised
at the quality. I did some of them with a pour temp (measured realtime
on top of the puck) from 202.5 to as much as 205.8 deg. depending on the
shot. I also varied the grind.

In conclusion, in addition to the overall length of time in the drying
or dessicating segment, the time from room temp to 225 deg might make a
difference.

My temperature readings are calibrated, NIST traceable, and certified to
better than 0.5 deg F in the roaster and to 0.2 deg F in the PF. The
timeconstant is under 0.5 sec. I am waiting for David to return his
roaster controller to me so I can recalibrate it and add an improvement.

Regards,

Jeffrey Pawlan


 
Date: 31 Oct 2006 12:09:12
From: DavidMLewis
Subject: Re: early roast profile affects 2nd crack temp

I- >Ian wrote:
> On 31 Oct 2006 11:48:37 -0800, "DavidMLewis" <DavidMLewis@mac.com>
> wrote:
>
> >I've seen something roasting the Hache Co-Op Sidamo that I don't
> >understand. I now have the ability to profile roasts fairly repeatably.
> >If I run the segment from 265 F to 295 F over 1'30", I hit 2nd crack at
> >440 F, which is a usual temperature for me to see it. If, though, I
> >take 2'30" for the early ramp, I don't see 2nd until 453 or so. 1st
> >crack doesn't seem to move, occurring at around 404 in both cases.
> >Ideas?
> >
> > David
>
> Are these bean mass temps or readouts from an iRoar or GeneCafe?

Those are bean mass temps; I'm using one of Jeffrey Pawlan's
computer-controlled Hottops; there are two thermocouples, one in the
air just beneath the central rod and one buried in the beans just above
the path of the stirring vanes.

David



  
Date: 31 Oct 2006 20:25:52
From: I->Ian
Subject: Re: early roast profile affects 2nd crack temp
On 31 Oct 2006 12:09:12 -0800, "DavidMLewis" <DavidMLewis@mac.com >
wrote:

>
>I->Ian wrote:
>> On 31 Oct 2006 11:48:37 -0800, "DavidMLewis" <DavidMLewis@mac.com>
>> wrote:
>>
>> >I've seen something roasting the Hache Co-Op Sidamo that I don't
>> >understand. I now have the ability to profile roasts fairly repeatably.
>> >If I run the segment from 265 F to 295 F over 1'30", I hit 2nd crack at
>> >440 F, which is a usual temperature for me to see it. If, though, I
>> >take 2'30" for the early ramp, I don't see 2nd until 453 or so. 1st
>> >crack doesn't seem to move, occurring at around 404 in both cases.
>> >Ideas?
>> >
>> > David
>>
>> Are these bean mass temps or readouts from an iRoar or GeneCafe?
>
>Those are bean mass temps; I'm using one of Jeffrey Pawlan's
>computer-controlled Hottops; there are two thermocouples, one in the
>air just beneath the central rod and one buried in the beans just above
>the path of the stirring vanes.
>
> David

Do the beans look the same in the two roasts at 2nd crack?


 
Date: 31 Oct 2006 20:02:19
From: I->Ian
Subject: Re: early roast profile affects 2nd crack temp
On 31 Oct 2006 11:48:37 -0800, "DavidMLewis" <DavidMLewis@mac.com >
wrote:

>I've seen something roasting the Hache Co-Op Sidamo that I don't
>understand. I now have the ability to profile roasts fairly repeatably.
>If I run the segment from 265 F to 295 F over 1'30", I hit 2nd crack at
>440 F, which is a usual temperature for me to see it. If, though, I
>take 2'30" for the early ramp, I don't see 2nd until 453 or so. 1st
>crack doesn't seem to move, occurring at around 404 in both cases.
>Ideas?
>
> David

Are these bean mass temps or readouts from an iRoar or GeneCafe?