HomeRoast Digest


Topic: Air Roasting Profile Precision (11 msgs / 246 lines)
1) From: Maryann & Dave Schellenberg
I just read David Schomer's article athttp://www.freshcup.com/where he 
comments on the importance of very precise temperature control in the 
brewing of espresso. His example is staying within three tenths of a 
degree error.
As a new coffee roaster this year, I have tried to follow in the steps 
of the pioneers, whose air roast profile recommendation seems to be:
    2 minutes to 265 F
    10 degrees / minute rise to 295 F
    30 degrees / minute rise to first crack
    10 degrees / minute rise to second crack.
I use a Variac with a split wired 1500 Watt popper to try to achieve this.
Of course, because I don't use a PID controller, I get some variation 
from this profile.
Has anyone satisfied themselves on how much variation from this will 
adversly affect the coffee taste?
I suspect those using  heat guns, grill/drum, convection oven/stir 
crazy, or other methods will find this irrelevant and extreme, but I 
know there are still some people out there using poppers and trying to 
control the profile by hand.
How much do you allow your temperature to vary from the ideal?
Dave S.

2) From: Rick.Farris
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You just do not know how tempted I am to suggest that it won't make =
nearly
as much difference as using a good grinder would, but I have way too =
much
self-control for that.  :)
-- Rick
----
11/4/2004 6:03:40 PM
Fair in San Diego, CA
62F (16C)  -  44% RH 
Wind From the West Northwest at 9 mph (17:28:30)
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3) From: Maryann & Dave Schellenberg
Rick.Farris wrote:
<Snip>
Besides, it's way too late for that - I use a good grinder now.
Dave S.

4) From: miKe mcKoffee
How true Rick, good grinder a must. But I'll make it even worse. I've been a
hardcore split wired boost voltage control follow those ramp rates profiler
for a couple years now. (The FrankenFormer roast controller sprang forth
from this home roast befuddled mind.;-) Toss it all out the window! Be one
with the bean! Wokking produces great results with no dials or thermometers!
But to answer the original question, the best way to know if varying ramp
rate changes flavor is to try the same bean different profiles! And no,
minor variations from target wouldn't be catastrophic, could be noticable
depending on the particular palate, bean, time of day, position of celestial
bodies... Or more accurately to answer the original question: vary from
target as little as possible is/was the goal.
Kona Konnaisseur miKe mcKoffee
URL to Rosto mods, FrankenFormer etc.http://mdmint.home.comcast.net/coffee/Rosto_mod.htm

5) From: AlChemist John
I still roast by my modified WB1.  I have not variac and control my profile 
by roaster tilt/air flow.  I am quite satisfied with my control and 
coffee.  I can basically hit any profile my roaster can handle, but it has 
taken a couple of years to get in turn with my roaster.
Sometime around 06:02 PM 11/4/2004, Maryann & Dave Schellenberg typed:
<Snip>
--
John Nanci 
AlChemist at large
Zen Roasting , Blending & Espresso pulling by Gestalthttp://www.dreamsandbones.net/blog/http://www.chocolatealchemy.com/

6) From: Ken Mary
<Snip>
IMO there is no ideal profile. I have done 2 minute roasts that were as good
as or better than any long profile. I use many different modded poppers to
give me different tastes. But one concept that appears to give me better
results is a very fast initial heatup, often in a preheated popper. At the 2
minute mark, my "better" profiles are 350 to 400F infrared bean surface
temp.
Have you tried different profiles and what were your results?
--

7) From: Maryann & Dave Schellenberg
Actually, since I started using a Variac, all my effort has been in 
trying to achieve the "ideal" profile, which gives me a total roast time 
of about 14 minutes.
Before I got the Variac, I used a popper at full power, and total roast 
times were about 6 minutes.
Of course, my memory of the taste is no longer reliable, making 
comparisons with later results impossible for me.
I confess to not approaching this in a very scientific way; each roast I 
do is of a different bean.
I don't enjoy the roast process enough to spend a lot of time at it, but 
I do enjoy the resulting coffee.
That's why I have relied on the reports of others, primarily those who 
do take a scientific approach.
Ken Mary wrote:
<Snip>
When you get temperatures like that at 2 minutes, what time and 
temperature would you get to second crack outliers?
I wonder how your infrared-measured temperatures would compare with my 
digital cooking thermometer, suspended vertically from a hole in the 
"butter dish". Compared to most of the temperatures I read here, mine 
would be about 10 degrees lower, e.g. first crack starts about 380 F for 
me, and second crack outliers at 430 - 435, which is where I usually stop.
Dave S.

8) From: Ken Mary
<Snip>
I can vary the time from about 4 to 8 minutes total roast time to first snap
of second. Most of my poppers are modified with separate air and heat
controls.
<Snip>
I read nearly the same second crack temps as you do, but I generally stop at
420 to 427. First crack temps are subject to the profile, but start at 370
for medium (about 5 minute) profiles but both longer and shorter start near
380 to 390. Short 3 minute roasts likely have an artificially high surface
temp. Long roast first cracks are delayed due to drying out the beans.
--

9) From: R.N.Kyle
<Snip>
snap
<Snip>
I have tried so many poppers that I found a few that unmodified they work
for different profiles. I have one that goes full city in 4 min, one at 6,
one at 9 and one at 12 so if I want a different profile I just use a
different popper. I used to use a timer and a thermometer, that is how I got
the information about the poppers but once I found that they were fairly
consistent I quit using the thermometer and the timer. I have the poppers
marked and just grab the profile I want.
I do have to say that since I made the Drum I mainly drum roast now, and I
do use a thermometer and a timer when drum roasting.
RK
Ron Kyle
rnkyle

10) From: Maryann & Dave Schellenberg
Do I understand correctly that the thermometer measures grill 
temperature, and is not inside the drum with the beans?
What sort of profile do you aim for, when using the drum?
Dave S.
R.N.Kyle wrote:
<Snip>

11) From: AlChemist John
If you are relieing on other peoples data, I would suggest getting that 
roast time down a little.  I found MY ideal in the 11-12 minute range.
Sometime around 08:27 AM 11/5/2004, Maryann & Dave Schellenberg typed:
<Snip>
--
John Nanci 
AlChemist at large
Zen Roasting , Blending & Espresso pulling by Gestalthttp://www.dreamsandbones.net/blog/http://www.chocolatealchemy.com/


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