After wandering a while in a Dalla Corte wilderness of umpteen grind, pressure, weight and temperature variables, I have found a sweet spot and a technique that brings this machine close to that LM Nirvana shot with its dozen flavors that I had at Bar Bambino in San Francisco in January.

First, I had to deal with a quirk of the DC. In my early days as a Silvia user, I was accustomed to using two hands to lock in the portafilter: one to jam it in hard and the other to hold the machine steady. Years of E-61 use after that spoiled me. Those E-61's will practically lock in with a pinkie finger. Well, the DC is more like a Silvia when it comes to lock-ins. If your grind is especially fine or updosed, the portafilter will gradually (sometimes not so gradually) spin out of the brewhead and make a mess for you.

Because of this, I was avoiding updoses and fine grinds. That was why my shots were so ill-defined, although tasty and predictable. It turns out that updosing and a super fine grind is exactly what gets the best from this machine. For a couple of weeks I have been dosing 18g. and turning my Cimbali Max Hybrid down below the "0" point. It's been coffee magic for me, as I have left Muddy Flats for two-handed Clarity Heights.

I'll give it a try.

I've been testing the machine for review, and have developed a deep and abiding dislike for the FOT OPV. The new production will be delivered with a brass, and, with luck, a less perverse OPV. I set the pressure to 9 bar on a blind filter and pulled successive shots after doing 1/8th turns (roughly a 1/2 bar change on the blind filter). The first few shots were weak like a lever machine, but relatively clean tasting. Within a quarter turn the taste changed to overextracted bilge -- nescafe with crema -- where it stayed until the OPV was completely defeated (screwed in so far it couldn't open). That's where I get acceptable shots (and a lot less of the annoying buzz bomb noises this pump/opv combo produces).

I suggest trying a few shots with normal doses ( ca 15 grams with the fat block or 17 grams with the thin one) and the OPV completely turned in (clockwise). It could be you are achieving the same effect in a more complicated way by using excessive grind and dose.

In any case, I suspect there was something very screwed up with the vibe pump set up as shipped previously. I'm getting the pump "upgrade" kit (the Ulka plus brass OPV is actually less expensive), and won't post an addendum on the review thread until I've completed the testing.

It's been my experience that machines with showerhead style diffusers (no dispersion screen) and a tall puck favour slightly more headspace. In other words, I'm surprised you say updosing to 18g improves taste.

Slightly OT question: Anybody know if you can swap the Dalla Corte Diffuser and screen onto a Vivaldi?

another_jim wrote:I set the pressure to 9 bar on a blind filter and pulled successive shots after doing 1/8th turns (roughly a 1/2 bar change on the blind filter). The first few shots were weak like a lever machine, but relatively clean tasting. Within a quarter turn the taste changed to overextracted bilge -- nescafe with crema -- where it stayed until the OPV was completely defeated (screwed in so far it couldn't open). That's where I get acceptable shots (and a lot less of the annoying buzz bomb noises this pump/opv combo produces).

After testing the Mini with Greg's Scace 2 Thermofilter, James Warren determined that his previous measurements with a blind filter overstated the pressure by 2 bar. So, any machines set to a blind filter 9 bar actually produce 7 bar with a continuous water flow.

I experimented with several different pressure settings and am pretty happy where I am now. So, I'll leave the further experiments to others.

Follow-on discussion split to Why difference in pressure between blind filter and brewing?

Marshall, for what it's worth, my "clarity" shots seem to be derived from a single basket.
Have you attempted singles?
Maybe that's less applicable with a full on pump machine, but I got lots of nice nearly 1oz singles on my former Anita, and wonderful espresso singles from my Cremina.
Just a thought.
Hope you're enjoying the journey.

IMAWriter wrote:Marshall, for what it's worth, my "clarity" shots seem to be derived from a single basket.
Have you attempted singles?

Yes, but singles are better suited to the Italian hit-and-run coffee bar style, than my relaxed sip-n-savor style of drinking.

Yeah, but your machine (and grinder) could probably crank out 3 "sip and savors" for every one of mine.
Had a thought...I tasted an incredible Sulawesi (brewed as drip from a Fetco) @ George Howells both at SCAA Atlanta. Absolutely the sweetest coffee I've had in a long time, and the cleanest Sulawesi ever (for me)
I wonder how that would do as an SO?
Not meaning to take you off topic there.


Edit...meant "booth"