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Topic: my rod has me reeling (dark roasts) (12 msgs / 315 lines)
1) From: Doug Hoople
Hi All,
The saga continues, and the truth is often stranger than fiction.
I've got the 8-cup Yama vacpot with either of a Cona or a Corning glass rod,
and I posted a while back on long drawdown times. I was getting 3-minute
drawdowns, when other listers were posting a far more normal 1-2 minutes.
At the time, the general conclusion was that my grinder was the culprit,
that it was a beat-up old toy burr grinder generating pulverized mud. That
led me to finally break down and get a Baratza Virtuoso from SM.
Before proceeding, let me just say that, in spite of what follows, the
coffee I've been drinking since Thursday has been much improved, cleaner and
more flavoful in every pot in the 20-30 (!!!) I've brewed with the new
grinder. So, no matter what, I'm pleased with the improvements.
Some of you may remember that I declared problem solved when my first batch
of coffee drew down at 1:05, on a setting of 30 out in a range of 0-40 (40
being coarser). That was a Costa Rican roasted to C+ (actually one of the
two pre-roasted coffee's in one of Tom's recent roasted pairings).
I later brewed up a batch of the Sulawesi Toraja Sapan-Minanga that serves
as our go-to origin here at home, roasted at Vienna, and noticed that the
drawdown times were in the 4- to 6-minute range. I started coarsening to see
if I could bring that down, and ran out of coffee at about 36, with drawdown
times still around 4 minutes or so.
I started panicking, thinking that something had come adrift inside the new
grinder.
In the meantime, as a control, I also had a pound of Sulawesi from the local
P@@t's, and all their coffees are roasted notoriously dark. Sulawesi takes
well to dark roasting, so that was our house coffee before we started
homeroasting. It's so dark, actually, that oils are swimming over the
surface of the beans.
Well, continuing on with the experimentation, I maxed out the grinder to 40,
ground up 60 grams from the heart of darkness, and proceeded to the brewing
step. Wow!!! 12-minute drawdown.
I won't run all the iterations. I've brewed a ton of coffee today, more pots
in one day than ever before.
I re-ran a pot of the Costa Rican C+, ground at 29 on the Virtuoso, and
repeated the 1:05 drawdown.
And pot after pot of the very dark roast, even at the coarsest possible
settings, came in at more than 6 minutes drawdown, some I stopped after 12.
So it seems that while a good grinder generates better, more consistent
output, very dark roast coffee presents additional challenges that might not
be addressable with a grinder.
Good thing I've weaned myself off the really dark, dark roast, isn't it?
If I really must have a pot of this dark stuff, then I'm going to have to
resort to the cloth filters in place of the glass rods.
Very interesting Saturday!
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2) From: Bob Hazen
Very interesting!  I have to ask:  Are you getting more fines with the 
darker roasts?
Bob

3) From: Doug Hoople
I don't actually know. I haven't done the analysis yet.
On Sat, Apr 4, 2009 at 4:11 PM, Bob Hazen  wrote:
<Snip>
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4) From: Doug Hoople
Ground a C+ and the very dark both at 30 on the Virtuoso. Examination with a
magnifying glass doesn't show a lot of difference, certainly not enough to
explain the drawdown.
Maybe I'm just not experienced enough to see it, though. I'll see if I can
borrow a strainer from a neighbor and try a bit of sifting.
Interesting texture, and the grounds do look surprisingly consistent under
glass, a rubble-strewn landscape.
BTW, tried my first pot of French press this morning, and it's the first
French press pot I've ever had at home that didn't taste muddy. Nice. The
grinder has definitely made a difference.
Doug
On Sat, Apr 4, 2009 at 4:41 PM, Doug Hoople  wrote:
<Snip>
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5) From: Brian Kamnetz
Doug,
I'm no expert at vac pot brewing, but it seems odd that you should
suddenly experience this great change, and that grind has no effect. I
wonder if you have lost your seal? Have you tried the vac pot recently
with no coffee, just water?
Brian
On Sun, Apr 5, 2009 at 3:59 PM, Doug Hoople  wrote:
<Snip>
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6) From: Doug Hoople
Hi Brian,
Yes, this is puzzling. But it's real. What's more, it's consistent. The C+
Costa Rican Helsar draws down actually a little faster than expected at
1:05. The Vienna Sulawesi Toraja slower at 4-6 mins. And the Vienna++
(French?) at 6-12+ mins.
The vacpot itself seems fine. The seal is perfect (I can't lift the funnel
with liquid upstairs). And with the cloth filter, the whole process is
entirely normal. Actually, with the cloth filter, even the darkest roast
drew down in 1-1/2 to 2 minutes.
Aside from the promising intellectual intrigue of this, there are any number
of practical answers.
1) don't drink such dark-roasted coffee! I started homeroasting precisely
because all the commercial outlets roast too dark anyway, so this is a
complete no-brainer. The only reason I have this bag of commercial dark
roast is for testing and comparison anyway, having just bought the Virtuoso.
No plans to return to drinking the stuff.
2) don't use the glass rod if brewing beyond Vienna. Use cloth filters
instead (I won't do this, as I can taste the taint, and, to me, the cleaning
ritual is punitive).
3) Brew French press instead. I just brewed a pot at the Virtuoso's coarsest
setting, and it makes a very nice cup of coffee. Not at all muddy.
Definitely different from the vacpot, but very nice in its own right.
BTW, while writing this, I just pulled out my Beehouse teapot, which has a
strainer in it, and have sifted the grounds from the light and dark roasts.
The amount of fines is, a near as I can tell, precisely the same!
Maybe the espresso aficionados can chime in here. I was reminded offline
that the darker the roast, the more days espresso brewers wait before
pulling their shots... something to do with CO2 levels?
Another possibility is simply that the oils in a dark roast are more and
separately concentrated, and that the oil is helping to form a seal at the
glass rod contact points.
All speculation. I'd love to have someone with real knowledge and/or data
who could enlighten us chime in right about now!
Doug
On Sun, Apr 5, 2009 at 1:24 PM, Brian Kamnetz  wrote:
<Snip>
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7) From: John Borella
I use a Mazzer Super Joly for vac pot grinding & have also experienced slow 
draw down times with the 8c Yama brewer I just got. The same grind that 
works beautifully in my Hario 3c & 5c tabletops resulted in a very slow 
return in the Yama. All 3 brewers are using the cloth filters & even with a 
coarser grind I find the big Yama pretty slow.
John

8) From: Doug Hoople
Interesting, John, that you're getting this with cloth filters. It's only
when I use the glass rod on the big Yama with dark roasts that I have
trouble with slow drawdown. When I use the cloth filter, the problem goes
away. Hmmm... the plot thickens!
Doug
On Sun, Apr 5, 2009 at 3:00 PM, John Borella wrote:
<Snip>
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9) From: Tom & Maria - Sweet Maria's Coffee
It makes sense to me, given the way darker roasts test in the little 
sieve I have compared to lighter roasts on the exact same grinder 
setting. Nomatter the adjustment, darker roasts create more powder 
and smaller fractional pieces than lighter roasts. They are so much 
weaker in physical form; have you ever taken a dark roast bean and 
just crushed it between your thumb and forefinger? Something you 
could never do at City+ or so. The way the water percolates through 
the grounds, all those fines end up at the seal between the rod and 
glass, and create added filtration. Darker roasts filter quite 
differently in paper filters as well!  It is amazing to me how much 
adjustment needs to be made for roast level, both because of the 
grind, but also how easily a darker roast is saturated with water 
than lighter roasts. Espresso people know this from the endless 
tinkering they have to do for roast variances... -Tom
<Snip>
-- 
-Tom
"Great coffee comes from little roasters" - Sweet Maria's Home Coffee Roasting
               Thompson & Maria -http://www.sweetmarias.com     Sweet Maria's Coffee - 1115 21st Street, Oakland, CA 94607 - USA
             phone/fax: 888 876 5917 - info_at_sweetmarias.com
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10) From: Jeff Oien
Tom & Maria - Sweet Maria's Coffee wrote:
<Snip>
And easier to eat.
Jeff
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11) From: maandjc
Hi,
  I have a Con Vac Pot and experience the same issues in dark roasts.  I prefer the lighter roasts but ocassionally roast dark and here's how I deal with it.  At the beginning of the trip south, I get a spoon or fork and stick it down into the coffee and in a very controlled and deliberate manner yet as gently and slowly as I can I press against the side of the rod. Any abrupt movement of the rod will dump more grounds into the bottom bowl, so I do this slowly and under maximum control. Due to the way the rod is sitting, I may have to press one side or the other.  When the flow  south reaches what I consider normal, I maintain pressure on the side of the rod for say, 10-15 seconds until the flow is established, then I withdraw the spoon or fork.  If I don't wait until the flow is established, the grounds will quickly clog up the flow and increase the vacuum. A couple of points in this regard:  The longer I've waited on a dark roast to do this, the more difficult, if not impos
 sible, it has become to control.  Vacuum will increase, more pressure will be required to nudge the rod and when I then when I succeed there is a large whoosh!! carrying  a lot of grounds south with it. I don't like the idea of applying a lot of pressure to the rod with a metal utensil (maybe I should be using a wooden spoon), with a glass bowl in close proximity, while trying to maintain the Cona firmly in it's stand.    At any rate, in a few instances, I have had a spoon or fork slip under a lot of pressure without catastrophe.  Still, I do this with utmost care and control and is something I feel I can manage.
Joe
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12) From: Doug Hoople
Hey Joe,
Thanks (!) for the report. Over the past couple of days, I've been letting
the consequences of this new piece of information settle. I've been hoping
to stumble onto something that made the problem more manageable, something
having to do with agitation patterns, settling patterns, something...
Two things I know.
1) With your confirmation and my own experience, it's clear that there are
challenges with vacpot and glass rod when it's a dark roast you're brewing.
Everything becomes more critical, not ever as critical as with espresso
(which is a universe of challenge unto itself!), but it's not a simple
matter of grind and go.
2) At this level of darkness, the quality and consistency of the grinder
acquire significance. I've tried the output of a couple of grinders, and
found that a better, more consistent grind can make the difference between a
stall and a decent extraction.
Maybe, Joe, with the technique you describe, it becomes possible again to
work with a less-than-perfect grind. I'll have to give it a try when I get
home. At the very least, it's a coping strategy that's known to work.
Thanks.
Doug
On Tue, Apr 7, 2009 at 2:17 PM, maandjc  wrote:
<Snip>
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