[Homeroast] Help! - Bad Shots

Larry Dorman ldorman at gmail.com
Thu Apr 19 22:21:19 CDT 2012


So...  I'm using an Andreja Premium these days and absolutely love
it...  I always use the double basket and have likely done at least
100 shots at this point and until about 15 minutes ago I've maybe
thrown away two.  I just got done throwing away four of them.  This
machine has an analog gauge that shows the pump pressure which I tend
to observe as one of the indicators of a good/bad shot.

I'm using a Rancillo Rocky grinder that's in good and clean
operational condition.  The grind is dialed in nicely.  I have both
some Sweet Maria's beans that I roasted about a week ago and some
decaf beans that I bought from a high quality local coffee shop and
which were roasted on the 14th.  I got great shots with both beans
yesterday without having to change the grind for either.

Tonight I set out to make some decaf espresso and all seemed to be
going well.  The grind was just what I expected.  My process was just
like what has been working fine.  The tamp looked good.  I went ahead
and started to pull the shot and when the pump pressure got to just 4
bars (which it always does almost right after starting) I started
getting a dark coffee like substance pouring out, then it slowed, and
the pressure went to about 8 or 8.5 bars.  Once the pressure got high
enough I started getting a little crema.  So I dumped this shot.

I adjusted my grind a notch finer, repeated the process, and got the
same results.  I tasted this shot thinking maybe the gauge was wonky?
(I new better since I got liquid entirely too fast and in volume.)  As
you might expect, it smelled and tasted terrible.  Another one down
the drain...

I then back-flushed a couple times and made sure the group was clean
thinking maybe there was a problem sealing.  I also adjusted the grind
just slightly finer still even though the grind really looked correct.
 I still got the exact same behavior.  I did an autopsy on the puck
and it appeared to be equally wet throughout with no hints of
channeling.

At this point I'm really starting to think that there must be
something wrong with the machine, but just to test I pull a shot from
the regular beans.  This shot is darn near perfect and might have been
improved only slightly by a very modestly coarser grind.  This makes
sense as I had adjusted the grind finer while troubleshooting with the
decaf.

Now that I knew the machine was fine I decided to try the decaf one
more time and with the exact same failed results.  Another attempt at
regular gave me a beautiful shot.  An autopsy of this regular puck
didn't show anything notably different from the decaf puck.

My regular beans are stored in a mason jar while my decaf beans are
stored in a plastic lined paper coffee bag that has been kept closed.
Again, I've had successful shots from this same batch of decaf
yesterday.

So...  what the heck is going on?  I'm really at a loss to explain
this one and since I'm trying to cut back on my caffeine intake, I
really want/need to be able to pull shots with the decaf.

Thanks for your insights...

LarryD



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