Bleeding pressurestat lever machines. (Especially 2nd gen La Pavonis) - Page 5

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Posts: 34
Joined: Sep 21, 2016, 4:45 pm

Postby EddyQ » Oct 21, 2016, 1:00 pm

DanoM wrote:I modded my 1984 group with a millenium type group plug, filed a notch in the dipper tube, and turned the group into a water heated group instead of steam heated. In turn I need a digital thermometer, k-probe, for watching the group temperature - not something everyone is interested in doing for sure. With that mod I can run the boiler hotter for better steam, dial in the shot start temperature repeatedly - shot after shot, and cool with only the use of the naked PF locked in the group while I grind and tamp the next shot.

Thanks DanoM. I have read this thread, but I guess I need to read it again. And I know I missed your very cool modification!
Pull after pull with no increase of temp . My millennium certainly does not do that. I'm curious what is the temperature you are measuring with your thermocouple? My meat thermometer (certainly not as good as a thermocouple) quickly reaches almost 100C after my first pull. I pull with a reading of 90-94C and pre-warm the group with a few flushes into my cup. I'll have to try cooling my portafilter to see how much heat gets removed between shots. Maybe I could pull shot after shot with that change of technique.

DanoM wrote: My pulls are very solid, and I don't do any steam flashing or fancy things like that. LIft the lever about 1/2, lock in the PF, raise the lever the rest of the way, count to 10 and I have a solid pull.

Oh, I failed to mention I had no spongy pulls with a medium roast that I started with in September and I followed your exact routine. This spongy issue showed up with a new batch of dark/oily roast I bought from a local roaster. It took me a pull or two to dial the grind for proper pull time, but then it was spongy and only 22gm final. I altered the grind and this did nothing. Very long infusion did nothing. This slight level ups/downs and lower dose fixed it. My next batch of coffee won't be so dark. I prefer medium roasts. But coffee itself seemed to contribute to a spongy pull.

Keep in mind, I am a beginner. I've had this La Pavoni for only a month and it is my first. But with help from threads like yours helped me adjust quite nicely to this machine. I'm liking it a lot! Thanks.

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Joined: Jun 06, 2013, 7:21 pm

Postby DanoM » Oct 21, 2016, 7:19 pm

I've replied to your questions over at the mod thread. I didn't want to take this one too far off topic.
Heat control of 1984 La Pavoni Professional