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Topic: Bean size-length of roast (7 msgs / 172 lines)
1) From: Vicki Smith
I just finished the second of two, 12 ounce roasts in my bread 
machine/head gun roaster. The bean of the day was the Guat Antigua 
Peaberry. I wanted to see how much I could vary the time to the edge of 
second crack by playing with the distance I hold the heat gun from the 
beans.
I roasted both batches until just as I saw/smelled the smoke beginning 
to change--at that point when I ask myself if I had actually heard the 
first tentative pop of second crack. One roast was done in ten minutes 
and the other took fourteen. I could have made the first roast even 
shorter, I'm pretty sure, but I didn't want to risk a bread machine wild 
fire.
When I compared the roasts side by side, I noticed that the beans I 
roasted for 14 minutes were not only a bit darker, but noticeably larger 
as well. I should have weighed the completed roasts, but what can I say, 
my bad.
How generalizable is this? How would you think it would impact taste I'm 
thinking shorter=brighter, but I don't know if the factors that lead to 
more bean expansion is meaningful as a sign of what would make this so.
Any thoughts?
vicki

2) From: miKe mcKoffee
<Snip>
You mentioned the 14min batch was slightly darker in appearance. I suspect
that the 10min batch is actually substantially lighter roasted the it
appears and there's more differnece than outwardly apprears between the
batches. Have you compared their grinds? There were some roasts brought to
the End of Summer Espresso Jam that appeared City+ to Light Full City
externally, but when ground actually closer to a light Cinnamon roast.
Suspect roasted too high heat too fast.
Holding the heatgun further away likely not only lowers heat at the bean but
also more evenly distributes the heat across the beans yielding more even
roast both across the beans AND in the beans.
But yes generally speaking faster roasts tends to be brighter with less
body. But too fast a roast doesn't allow a fully developed light (or darker)
roast, though more noticable in a lighter roast since a fast external dark
roast will have the internal at least fully light roasted while a fast
external light roast internally may not be fully roasted. OTH too slow a
roast will go beyond building body and result in a flat lifeless baked
taste. All a matter of balance. Bean expansion wise a slower profiled
lighter roast should have about the same bean size expansion as a darker
roast I'm fairly certain.
Kona Konnaisseur miKe mcKoffee
URL to Rosto mods, FrankenFormer, some recipes etc:http://mdmint.home.comcast.net/coffee/Rosto_mod.htmUltimately the quest for Koffee Nirvana is a solitary path. To know I must
first not know. And in knowing know I know not. Each Personal enlightenment
found exploring the many divergent foot steps of Those who have gone before.

3) From: Ken Mary
<Snip>
There is a correlation between bean expansion and finish temperature. Also,
very fast (under 4 minute?) roasts will have a larger expansion compared to
longer profiles. General Foods patent 4,501,761 gives the glass transition
temperature as 210 to 225C or 410 to 437F. This is where the bean becomes
soft. Roasting to a finish above 437F should result in little additional
expansion.
The same patent gives a "MET" of 240C or 464F to avoid charring. By trying
to roast faster with a higher environment temperature, you may be decreasing
the roast quality. I say MAYBE because my 3 rpm low speed drum roasts do not
lose quality, but they do taste different. Such low drum speeds result in
incomplete mixing and possible overheating of beans in contact with the drum
wall too long. This is the same effect as a too high heat gun temperature.
The shorter = brighter effect holds mainly for those beans that have some
brightness to begin with, especially Kenyas. To get a "Kenya brightness"
from a Sumatra or Brazil is practically impossible. I have found that
forcing a low brightness bean to higher brightness, by shortening the
profile and minimizing drying, often ruins the taste. It is better to focus
on the origin taste qualities of the bean, and adjust the profile to
maximize those qualities.
--

4) From: True, Dennis W. FC1 (CVN69)
Ok so how do you reverse that taking a high brightness t a lower
brightness?
Dennis
.
The shorter = brighter effect holds mainly for those beans that have
some
brightness to begin with, especially Kenyas. To get a "Kenya brightness"
from a Sumatra or Brazil is practically impossible. I have found that
forcing a low brightness bean to higher brightness, by shortening the
profile and minimizing drying, often ruins the taste. It is better to
focus
on the origin taste qualities of the bean, and adjust the profile to
maximize those qualities.

5) From: Michael Wascher
Usually hot fast roasts are brighter and cooler slow roasts are less bright.
So if you want brightness go with a popper. To tone it down use a drum
roast.
I have an original Poppery that has a thermometer stuck through the lid and
with only the heating element connected to the switch. I've tried extending
a roast my watching the temperature & switching the heater on & off. It did
mellow the brightness a bit, but I couldn't get close to a drum roasted
taste.
--MikeW
On 9/6/06, True, Dennis W. FC1 (CVN69)  wrote:
<Snip>
-- 
Be who you are and say what you feel, because those who mind don't matter
and those who matter don't mind.
  - Dr. Seuss

6) From: Vicki Smith
I haven't sampled it yet, but my ten minute roast may have squeaked by. 
I ground some, just to check, and I didn't get that tell tale wood chip 
look I have sometimes seen in badly under roasted roasted beans (not 
mine of course ;) )
I know that a short roasting time won't add brightness in a bean that 
doesn't have it to begin with, but I am not a huge fan of acidity in 
coffee--a little goes a long way in my book.
I'll be interested to see if there is a trade-off between body and 
brightness in my two roast levels. I'll be trying some of both roasts on 
Saturday. I'm going to NYC Friday, and won't get my own coffee that 
morning as mine will be packed away, and my hosts in Calgary, my jump 
off point, Friday AM will have their own homeroast to sample.
Vicki
miKe mcKoffee wrote:
<Snip>

7) From: George Birchard
This is a multi-part message in MIME format.
Ken Mary wrote:
<Snip>
I have had trouble getting my tight little Panama peaberry beans to 
expand in the little air roaster.  They come out tasting bland or burned 
depending on roast length.  Are you suggesting that high initial temps 
would help roast these tight beans better? No way did I get the quality 
that Tom described.


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