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Topic: New profile experiments -- not by time/temp but by development (12 msgs / 354 lines)
1) From: Jim Schulman
Hi all,
The difference between roasting dark or light is pretty clear. 
So is the result of going slow or fast after caramelization 
starts (i.e around the first crack). But timing versus taste 
differences before the first crack continue to be a head 
scratcher for me.
So barring some detailed insight into the chemistry, I'm going 
to try a new simple theory: "The best roast profile below the 
first crack is the fastest one possible where all the beans stay 
a uniform color throughout (or as uniform as possible throughout 
for the DPs and preblends)" 
This seems likely enough to be worth checking. Stalling a roast 
at low temperature (so the color isn't changing) is said to bake 
the beans (don't really know about that one), so some speed, at 
least, is a positive. Also, in my experience at least, roasts 
that are uneven early always taste worse than ones that aren't; 
so too much speed is no good. These two adages add up to this 
simple "roasting theory."
So for the next few months, I'll roast using my eyes, instead of 
a clock and thermometer; record the profiles, and compare them 
as often as possible to both longer and shorter roasts. Don't 
know if I'll come up with anything worthwhile; but it'll be a 
nice way to keep myself amused while I'm roasting.
Jim

2) From: HeatGunRoast
--- Jim Schulman <jim_schulman> wrote: 
> Hi all, 
> 
> The difference between roasting dark or light is pretty clear. 
> So is the result of going slow or fast after caramelization 
> starts (i.e around the first crack). But timing versus taste 
> differences before the first crack continue to be a head 
> scratcher for me. 
> 
> So barring some detailed insight into the chemistry, I'm going 
> to try a new simple theory: "The best roast profile below the 
> first crack is the fastest one possible where all the beans stay 
> a uniform color throughout (or as uniform as possible throughout 
> for the DPs and preblends)" 
 
Hi Jim,
I'm really pleased that you are onto this line of inquiry.  Since I am working with nothing but my senses and a timer (the timer more to decide and record where the roast has been than to determine where it's going), this is exactly the kind of theory-building I'm hoping for.  For what it's worth, I've experimented with all sorts of timelines getting to first, and I keep getting back to 6.5 minutes (more or less).  Longer seems to produce no benefits and the more gradual ramp makes me nervous about stalling.  Shorter makes it difficult to get an even roast.  I'm also noticing some differences around what you've (I think it's you, maybe not) referred to as "pushing" the ramp.  In my case, I notice improve roasts when I give a strong boost of heat as first starts to force a more rapid shorter-duration first crack.  I hope you'll watch for this.  I've got some more thoughts about what happens after first, but I'll wait 
 for your
 next report.
Martin
> 
> This seems likely enough to be worth checking. Stalling a roast 
> at low temperature (so the color isn't changing) is said to bake 
> the beans (don't really know about that one), so some speed, at 
> least, is a positive. Also, in my experience at least, roasts 
> that are uneven early always taste worse than ones that aren't; 
> so too much speed is no good. These two adages add up to this 
> simple "roasting theory." 
> 
> So for the next few months, I'll roast using my eyes, instead of 
> a clock and thermometer; record the profiles, and compare them 
> as often as possible to both longer and shorter roasts. Don't 
> know if I'll come up with anything worthwhile; but it'll be a 
> nice way to keep myself amused while I'm roasting. 
> 
> Jim 
> 
> homeroast mailing list 
>
http://lists.sweetmarias.com/mailman/listinfo/homeroast
> To change your personal list settings, seehttp://www.sweetmarias.com/maillistinfo.html
Martin

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3) From: Ed Needham
In my grill drum roaster, I keep the heat full blast until first is rolling
pretty god, then cut it back to allow a long silence between first and
second.  My assumption is that there are complexities of taste that develop
during this time and I want to allow a slow simmer until second hits and then
kill the heat all together.  My experience with a roast with short (or none)
time between first and second is that the coffee is good, but not very
interesting.  Extending the time between first and second seems to bring out
the best in my roasts.
***********************************************
Ed Needham
To Absurdity and Beyond!
homeroaster ... d.o.t ... com
***********************************************

4) From: HeatGunRoast
Thanks for the response Ed.  In spite of some misleading questions I've asked, both
you and Jim S. have posted several descriptions that are very useful for how to
THINK ABOUT roasting as something very different from how to DO roasting.
My guesswork coffee science hunch is that by "pushing" a first crack (quick ramp)and
shortening the strong crack duration to, on average, 20-30 sec., I get an earlier
start on whatever good things happen between first and second without a
correspondingly shorter roast which, for most my roasts (just into second) now end
at 10-13 minutes. This short-duration crack, I think, is more possible since I've
increased the time I take to get to first.
Of course, this is all roaster-specific, and you and I are not exactly using
off-the-shelf, plug-and-play roasters. For example,"full blast" for me is very
air-blast popper-like and could get me to a first crack in 3 minutes.  So I keep
things slower to start, but with more forceful air.  Just guessing, but I believe
this heats all the beans more evenly; next (usually just into the yellowing) I slow
the air volume but raise the heat to what is for me, "moderate," until 5 1/2 to 7
minutes. At the first few cracks, that's when I hit full blast. Like you, I ease up
to extend the roast after first.  If you were plotting your ramp to first, would it
be pretty much of a straight line or would it curve up as you got near or into
first?
Martin  
--- Ed Needham  wrote:
<Snip>http://www.sweetmarias.com/maillistinfo.html=====
Martin
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5) From: Jim Schulman
On 11 Aug 2003 at 21:56, HeatGunRoast wrote:
<Snip>
This is Jim. I go about 20F/min before and through the first 
crack, and 10F/min to 12F/min afterwards. 
I've also experimented recently slowing down to 12F/min as the 
first crack starts, and going through it more slowly. My 
experience in the Mika roast off suggests that this may work 
better for some beans. I used to think going too slow through 
the first gave a harsh taste. With the Mika, it was exactly the 
opposite. I had done about a dozen fruitless roasts of the bean 
without trying that, and only found out by accident, tasting 
other's profiles. So from now on, if I get harshness, changing 
speed during the first crack either up or down will be the first 
thing I try to fix it.
Jim

6) From: Ed Needham
If there was an accurate and reliable way to measure actual bean temperature,
descriptions between roasters would be easier and more informative.  I've got
a 12" dial thermometer that I stick into the bean mass as they are roasting,
and it gives me a better idea of what the beans are doing.  I can then
compare even when variables change, such as batch size (although very small
batch sizes don't immerse the thermometer tip enough to get a good read), or
bean type (where the time to first and second cracks may be different from
bean type to bean type).  I can then say, "ahhh, this bean has a robust first
crack at 410F, and the other bean type started at 415F".  That's more helpful
than roaster temperature when trying to understand the roast dynamics.
***********************************************
Ed Needham
To Absurdity and Beyond!
homeroaster ... d.o.t ... com
***********************************************

7) From: Derek and Pat Savanella D.B.A. Heavenly Beans
I think Tom misses us. I know there haven't been any new coffee arrivals and
reviews for me to drool over.
James

8) From: jim gundlach
On Thursday, August 14, 2003, at 02:08  PM, Ken Mary wrote:
<Snip>
Do you think an IR thermometer could measure bean temperature while 
roasting in a wok?
How expensive and accurate are they?
Jim Gundlach

9) From: HeatGunRoast
Yes, the IR works for a wok.  At least for beans in my dogbowl.  I have gotten consistent readings, but I have a fairly small target that's also easy to miss.  I have one of the cheaper/cheapest, and it's a cool little gadget.  +/- $35.  That said, it's not very convenient (especially in my case with a stirrer in one hand and the heat gun in the other), and by pointing it down onto the beans, the readout is upside down.  Then, of course, you have to reach for a pencil to write down the temp while glancing at the timer and paying attention to the beans.  At this point, I forgot why I cared about the temperature. I do intend to go back to it, though, and give it another shot. 
Martin
jim gundlach <gundljh> wrote:
On Thursday, August 14, 2003, at 02:08 PM, Ken Mary wrote:
> Even an IR
> thermometer sees only the visible surface of the beans within its spot
> diameter.
Do you think an IR thermometer could measure bean temperature while 
roasting in a wok?
How expensive and accurate are they?
Jim Gundlach
Martin

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10) From: Jason Molinari
I have an IR thermometer for my RC engines. It $70 and they are VERY accurate...BUT! i don't know if they will be valid for coffee in that they have their specs set to measure items with an emissivity of 0.95. If the beans are not 0.95 your readings will be way off.
jason
<Snip>

11) From: Rick Farris
I remember this topic from about a year ago.  I think it was here, but
maybe it was A.C.  At any rate, the consensus was that coffee beans
*are* close enough to 95% emissivity that the IR meter is at least as
accurate as a thermocouple as long as you're reading the beans directly.
Trying to read through glass won't work, though, so air roasters that
don't have open tops are generally out.

12) From: Oaxaca Charlie
--- jim gundlach  wrote:
<Snip>
 I got one for about $70 from Radio Shack. They are acurate,
but, the beans have to be dark enough for an acurate reading,
and the IR has to be very close, or it'll be reading the air
temp between it and the beans, too. If you get really close the
darn thing melts. Kinda fun to play with, for a while, but the
reading (very quick response) jumps around so much you never
know what the real bean temp is, I'm afraid. I haven't taken
mine out of it's case in a while.
  Charlie
=====
Brick Oven Roasting in British Columbia
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