[Homeroast] Reflections on Roasting Fundamentals

Ed Bourgeois edbourgeois at gmail.com
Sat Jun 28 16:04:27 CDT 2014


There's understanding the dynamics and control of the roaster and then
there's understanding the beans. The beans have much to do with chemistry
that happens with a temp. and then duration/time factor. We know that
coffee is extremely complex in what it contains. If there are 1000 +/-
things in coffee we can't consider all of them when roasting. But I'm
trying to narrow down to the few that make the biggest difference in the
resulting outcome. George Howell's clean and sweet concept makes sense to
me. Once I can accomplish clean and sweet then I can consider nuances in a
specific lot to adjust to preferred tastes. Sweetness is pretty much
directly related with what is done with the sugars and presently feel that
maybe chlorogenic acids transforming to chlorogenic lactones may be the
biggest contributor in a clean roast, other than heat abuse ie scorching.
There's development of sugars in the early ramp but the key time is once
they hit the melting/reaction point at about 365f. So my sweetness clock
starts then with considerations of clean sweet and caramel goodness as the
optional preference factor. Chlorogenic acids reaction temp. seems to be
around 405-408f. So to me a bad stall is not a lack of rate of rise but
more allowing the bean temp to fall below the needed reaction temp. or
stalling the reaction. The grassy/vinegar nasty acidity vs the transformed
more pleasant acidity. This all being much more critical with lighter
roasts.
Much of what I just said is work in progress and may be a bunch of bs at
this point in time.



On Sat, Jun 28, 2014 at 3:48 PM, John Monteleone <johnmonteleone at gmail.com>
wrote:

> This is a great dialouge.  I've been trying to figure out.  I have been
> using the Quest for about 4 months and I'm starting to get a better
> understanding of a roast curve.  Using a thermacouple I track the
> temperature every minute.  I have not been able to extend the time between
> the first and second so I liked the recommendation to back off the power
> prior to first crack.  My first crack has been pretty predictable.  I
> wonder if someone could comment on my roast curve and temps.  My beans have
> been Kenyans and Guatemalans.  Leading up to first crack, the temperature
> inside is rising 8 or 9 degrees celsius per minute.    My first crack has
> been hitting around 9 minutes at 190 to 192 degrees celsius.  That is when
> I turn down the heart and turn up the fan.  (i will change that now)  I
> have been ending the roast around 2 minutes later before second crack at a
> temperature of around 205.  This is right before second crack.  My question
> is:  what does the temperature ramp look like leading into first crack and
> prior to second crack if you are trying to extend the time to almost 3
> minutes.  Do I need to get to 200 at the very least.  How much higher.
>  What would a stall look like.  Would it stop at 192 and not really
> increase.  Any comments would be appreciated.
>
> John
>
>
> On Sat, Jun 28, 2014 at 9:52 AM, miKe mcKoffee <mckona at comcast.net> wrote:
>
> > My Aricha profile in brief:
> > Charge through drying stage ~5min ~300f (bean mass)
> > Tanning to start of first ~7min ~400f
> > Start of 1st to EOR ~2:30min 425f drop
> >
> > HOW you would achieve going from ~15f/min ramp approaching 1st to
> ~10f/min
> > ramp hitting 1st to EOR with RK setup can't say exactly since I'm not
> using
> > that roasting tool. How you "slam on the brakes" ramp wise is the big
> > question. I use a combination of dropping flame AND big increase in air
> > flow
> > (flushing hotter air out) coming up on 1st. As 1st starts in earnest
> flame
> > remains down and reduce air flow (reducing convection rate). Air flow is
> a
> > tricky thing yet huge in controlling roast and roast results especially
> > light roasts. On the one hand increased air flow can/will increase
> > convection once stabilized to higher air flow, on the other it can blow
> > current hot air out... I've roasted around 10,000 batches on my USRC 3k
> in
> > 6-1/2 years and think barely really starting to get a good handle on it!
> I
> > have other coffees drop lower than Aricha, current lowest 416f, and still
> > able to get a good finish stretch with end ramps approaching only 6f/min
> > without stalling. All about learning to control your roaster, Art AND
> > Science.
> >
> > It's easy to turn beans brown, it's a lifetime Journey learning to make
> > beans sing.
> >
> > Slave to the Bean miKe mcKoffee
> > www.CompassCoffeeRoasting.com
> > URL to Rosto mods, FrankenFormer, some recipes etc:
> > http://www.mckoffee.com/
> >
> > Ultimately 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.
> >
> > Sweet Maria's List - Searchable Archives http://themeyers.org/HomeRoast/
> >
> > -----Original Message-----
> > From: Homeroast [mailto:homeroast-bounces at lists.sweetmariascoffee.com]
> On
> > Behalf Of kevin creason
> > Sent: Saturday, June 28, 2014 9:20 AM
> >
> > Do you start off higher and then taper off, or still start lower + ramp
> up+
> > taper off before snap?
> > On Jun 28, 2014 10:57 AM, "miKe mcKoffee" <mckona at comcast.net> wrote:
> >
> > > Slow the ramp as you're approaching 1st...
> > >
> >
> >
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> >
> >
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-- 
Ed Bourgeois
Amherst MA.


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