hello jj,
i am only operating a brewtus iv for a couple of months, so i'm not
exactly an expert. but since no-one else seems to be responding, here
are my thoughts.
have you measured the pressure against a blind filter again, is it still
at 10 bar? i think you should check this first.
have you tried to go finer in the grind again? you could just offer too
little resistance with your coffee-bed for the pressure to build up.
all the best,
guido.
Hi, I am new to this group and would love to hear some comments
regarding my problem.
For starters I just recently purchased a new Brewtus IV, along with a
Baratza Vario W grinder and Espro (calibrated) tamper.
I am relatively new to the espresso world and thought that this group
of equipment would minimize some of the variables that can have an
adverse effect on shot extraction. The temperature of the Brewtus is
at the factory setting 96 degrees C (approx 205 F) and I'm using a
naked portafilter (for assessment purposes)
My goal was to attempt to achieve an 2oz pull in roughly 25 seconds.
I would use this as a baseline and then tweak from that point.
Ultimately, taste would be my guide.
On the first day of pulling shots I will admit that I didn't really
have a plan nor did I keep track of times and volumes. Big mistake.
I ended up getting shots that where either took too long or too quick
to pull. The shots either looked like crude oil, 75% crema or
something in between. Taste ranged from almost undrinkable (crude
oil) to something that you would expect to get from one of those
roadside coffee kiosks (you'll drink it because it's the only place in
town). One thing I did notice that the brew gauge frequently
indicated 4 to 5 Bar during the extraction.
The next day I decided that I would chart my pulls in an attempt to
resolve the problem.
I started by adjusting the OPV by using a blindbasket on the
portafilter. The factory setting was at 12 Bar which I have been led
to believe is too high. I adjusted the setting to 10 Bar which now I
believe might still be a little too high (9.5 Bar). Anyways the
current setting seems to be better than the factory setting.
My methodology was the following: I would start by setting my grinder
at a very fine setting, pull a shot, measure volume/time and adjust if
necessary. I ll spare you all the details (this is getting very
longwinded I know) but will provided a summary. Basically the first
shots (with a very fine setting) were very dark in colour and took
approx 60 seconds. Brew pressure measured at 9 Bar. I then made the
grind increasingly more coarse. The dose size (14 grams) would remain
the same. My hope was that I would be able to reduce the shot time
and maintain the brew pressure. What ended up happening was that the
shots times did decrease to a point and brew pressure remained
consistant. Then mysteriously brew pressures would only climb to 4 or
5 Bar after pre infusion. Towards the end of the shot (at the point
where blonding has occurred and the fluid has changed to a clear
state) the brew pressure shoots up to 9 Bar (I realize that I am
allowing the shot to continue too long once it has reached this
stage).
I then tried pulling shots with a 16 gram dose using the same
methods. Basically the same pattern occurred, full brew pressure with
the finest settings although very long shot times. Once the grinds
became more coarse, brew measure failed to reach more than 4 or 5 Bar
and only reached 9 Bar well after the shot should have ended. The
same pattern occurred at 18 and 20 grams.
The naked portafilter suggests that tamping and ground consistency is
OK. The fluids tend to first appear around the perimeter and then
focus to the center. There is a 'barber pole' effect until blonding
occurs. Sometimes is does take a few more seconds before a single
funnel occurs but this doesn t seem to effect the shot times and
volumes that I have been getting.
I ve run out of coffee for now and probably could use a break.
Any suggestions would be greatly appreciated.
Thanks,
JJ
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