I checked on the Vario calibration this morning:
- empty hopper
- both macro and micro levers at the coarsest setting (i.e. at the bottom)
- brought the macro lever all the way up, and as I brought the micro lever up to the midpoint, listened for a change in motor speed/sound
- didn't hear any change, so I turned the calibration screw clockwise until I did

This is where I left the grinder set for the following shot.

Let the PVE heat up during the grinder calibration, drew off false pressure, let it cycle a couple more times. Did a very basic tamp (maybe leaning on the soft side) & pull as Mike suggested.

There wasn't much resistance when the lever came back up, so I had my hand manually slowing the lever's ascent. About a quarter to third of the way up, there was a bit of a jerk--would that be the puck getting displaced? About two-thirds of the way up the lever slowed down on its own and I let go. Unfortunately I lost track of time for the extraction because I was so focused on the lever.

Not as sour this time: previous attempts were always full-barrel sour from the get go. This one was more at the middle/back-of-the mouth sour. Very little crema. I'd describe the shot as both thin and muddy, but take that diagnosis w/ a grain of salt since I'm only marginally better at describing coffee than wine and the latter not at all. Unfortunately that was the last of my Intelligentsia which was bordering on two weeks old.

Based on the slackness of the lever on its ascent, still too coarse of a grind/beans too old/tamp too soft/uneven?

peacecup wrote:IT IS NOT TOO COLD. The OE strips never even hit 90 C on the Export unless you overheat the group.

That's gratifying to know.

From the Lusso temp tests with a Scace thermofilter, I was expecting to see the strip register temps >200F.

I guess the temp strip will just serve as a warning that the group has overheated. I assume either the strip is not very accurate and/or its placement on the group makes for misleading temperature readings.

Thanks for chiming in, btw--your posts on this forum were a significant contributing factor to my selection of the Export.

I think that if you need to slow the lever ascent by hand (like you would with no coffee in the PF), then you either have a hole in your puck (channeling?) or the grind is still too coarse. The Vario should have no trouble choking the PV group, but you wouldn't want too because you would have to wait a while before removing the PF for the pressure to slowly drain on its own.

Just a thought... can you try WDT-style stirring of the coffee before you tamp (or stirring the coffee around in the catch bin from the Vario before you pour the coffee into the basket)?

The lever resistance won't kick in until part of the way up - it may be as far as horizontal before it catches, depending on the grind and dose. You shouldn't necessarily expect it to catch right above the bottom preinfusion point.

Well, I'm traveling for the next few weeks so won't have a chance to try anything further till I'm back. At least I'll have a chance to pick up some freshly-roasted beans from a reliable source just before I head back.

Will try and pick up a bottomless pf and properly sized tamper as well, which will hopefully assist in better diagnosis and correction. Thanks for all the suggestions!

I like traveling, but I hate being away from my Export. Whenever possible I take it with me. I think her last voyage was the ferry from Sweden to Finland, upon which she considerably brightened the journey, operating from the stateroom desk.

The bottomless PF wll help - let us know how you progress.

PC

Just returned home with new gear from Orphan Espresso and fresh beans. Brought back some Blue Bottle Hayes Valley Espresso that was roasted on Thursday, as well as some Yirgacheffe and Kenyan beans just roasted yesterday from the Coffee Factory in Seoul.

First shot with 14g of Hayes Valley was also the first good shot I've made on the Export.

For reference: used a very find grind on the Vario, just a stop before the point I hear the grinder's sound begin to change (as when calibrating)--I'll try a little coarser next time. Used a dosing funnel and slap shot with a light-to-medium tamp. First pull, held for a 10-count, let the lever go up 3/4 of the way and pulled back down for a 3-count. Only yielded a 3/4 ounce--nice, rich heavy mouthfeel, chocolatey, with good crema. Very last sip was a bit sour-ish, but by far the best shot I've pulled since getting the machine.

Still have a lot to learn, but many thanks to everyone for the helpful advice.

Incidentally, I got to pull a shot last week on what I'm almost certain was a La Marzocco GS/3 at the Twitter offices in San Francisco. I managed to pull a passable shot my very first time on a machine I'd never even seen in person before. There were other folks waiting behind me, so I didn't have the luxury to try more than a single shot, but that's a nice piece of kit. And Twitter sources their beans from Sightglass. I'd almost want to work there just for their coffee setup =)