Jim, so you wipe the group screen after your session, but that only cleans the surface oils...wouldn't there be a whole lot more behind the screen because it's sucked through during the pressure release phase?

I now get first shots as good as second shots. The Elektra group has very little volume from the three way to the screen; so it may be machine dependent. Ian, with an E61 box, advised doing a backflush with waste ground coffee before beginning a session.

As usual for all my advice; I never do anything unless I can taste the reason.

another_jim wrote:Ian, with an E61 box, advised doing a backflush with waste ground coffee before beginning a session.

You mean with a blind filter? Like a real backflush cleaning operation? Driving coffee/oils/grounds back into the group?
Interesting. Remarkable. Looking for words.

So the backflush 3-way implementation actually is a design error?
You would want a dedicated tube into the headroom between coffee bed and shower screen through which to release the pressure at the end of the shot.

Or, as I pointed to before, on an E/61 machine, switch off the pump just before the end of the pull, with the E/61 lever in the middle position - now pressure in the headroom presses coffee out whilst pressure ramps down and there is (almost) no flush through the pressure exit. I have seen Italian barista do this almost always on E/61 brew head type machines and some of them say they can taste the difference.

When I dose low and hence grind very fine, and at the end of the shot push the E/61 lever back all the way as fast as possible, I run a big chance the coffee puck is hanging on the shower screen when I take the portafilter off. The procedure above would give me a clean shower screen (towel and/or Pällo brush).

Regards
Peter

Or you can do what all (good) coffee bars do.
Clean the machine with detergent daily, pull a garbage shot or two to start the session (and "season" all metal).

That might be a little much for my single morning shot.

another_jim wrote:As usual for all my advice; I never do anything unless I can taste the reason.

And that is a sound one!!
I guess the first shot issue dwells in cafes and not at homes; I always clean my group with a paolo brush after session and backflush with water (detergent backflush I do when I do the periodical cleaning). On this rare occasions when my sessions became longer, I cleaned the group as usual after the last shot before the break... doing it purely on my intuition I'm happy to read these:

another_jim wrote:The effect is virtually eliminated if you use a cloth or sponge to scrub off the group screen before idling the group.

cannonfodder wrote:Knock out the puck, pulse the pump for a few seconds to clear the screen, wipe the screen with a bar towel, pulse the pump again to rinse out the portafilter, wipe it out and put it back in the group. If I am pulling multiple shots, then I will wipe the portafilter out, a very short pulse to rinse the shower screen of grinds and prepare my next shot.

If I pull back to back I do it exactly the same way.

Jim, thanks for clarifying.

another_jim wrote:...The issue I was mentioning, and which Ian discovered, concerns water insoluble coffee oils in the group... These do not rinse off in a flush (water insoluble), but do get dissolved by follow on shots.

After reading some of that thread, I began to wonder if that "being dissolved by the oils from the follow on shots" thing was actually what was going on. Clearly there's some oil exchange or there wouldn't be a flavor contribution by the old stuff... but I do wonder if what's actually happening is that the baked-on oil just gets a coat of fresh oil? After all, if coffee oil is such a good cleaner, where's that buildup come from at the end of a long day of pulling shots on a commercial bar?

That's a good point. I pull shots at home, so I have no way of telling how it works in a cafe. It's clear there's a lot more challenges when pulling hundreds of shots under time pressure than pulling a few at leisure.

Most of you seem to wipe your filter basket. After my first shot, water gets run through the Alexia, a quick brush on the screen, and a final few seconds of flushing to remove any debris. I then change to a fresh filter basket. Second shot is still better.

Just pulling 2-6 shots a day I see a light buildup of old coffee oil on the inside of the Speedster's screen assy. after 2-3 days. I typically do a detergent clean every 5-6 days, swap the screen mid week, do nightly plain water backflushes & follow the between shot/after shot regiment I detailed before. As long as I follow this routine I get some excellent 1st shots that I can only hope are equaled by the next one.