Can anyone explain this? I've had my Europiccola Millennium for a couple of years now, and I am getting quite comfortable with the machine. Rarely, if ever, a sink shot. The acceptable shots started when I started using a KYM hand mill, that I got from Orphan Espresso, and replaced the Ryton piston with a brass one. I also use a correct size 51mm tamper. The conventional wisdom that a heavier tamp will result in more resistance when pulling the shot doesn't seem to be the case. When I tamp with just slightly more weight than the weight of the tamper -- just enough to polish off the top of the puck -- I encounter significantly more resistance during the pull than when I use 30 pounds of pressure and a polishing twist. I never tap the portafilter for fear of breaking the coffee seal. I'm not complaining, I am just curious. Has anyone else has experienced this? I've seen a video where an Italian barista seems to barely tamp the portafilter before putting it into the machine.

Ray - I have almost the identical set-up - a Europiccola Millennium and a hand grinder from OE. And I've had the same thing happen to me on more than one occasion. Most of the time for me, if a heavy tamp results in less resistance it always looks to be because of channeling.

The guess I'd venture here is that since a heavy tamp compresses everything more, there is less room for manual error. For example, say you twist the tamper off the puck ever so unevenly at the end of the tamp - with a lighter tamp the puck may have the "give" to absorb this error - whereas with a heavy tamp there is nowhere for the uneven energy to go besides causing the entire puck to shift, breaking the seal with the portafilter.

This is certainly just a guess however - I could be way off here - and would also be interested in other thoughts.

Ray-
Dovetailin' here... Are you distributing the grounds in the basket before tamping? See here..Dose, Distribute, Tamp, Repeat On the contrary, I have not been using much of a tamp lately on my Pavoni just a leveling off tamp and having great results. Your problem sounds familiar... At work I am currently getting my bell rung by my Gaggia D90's seeming inconsistencies, so God only knows (or maybe someone here on HB)

You could use a bottomless to check for channeling.

I have a Pavoni (1976) and a wall mounted, super fast, KYM hand grinder from OE - made all the difference to my shots. I tamp hard, real hard, but only because I pack a minimum of 16 grams of coffee into the PF. The pressure of the column of water (especially after 2 or 3 Fellini pumps) far, far exceeds the measly pounds I put into it. If I could stuff my basket with just as much coffee, and use less tamping strength - I do it, and I'm sure my shots would be no less glopilicious and syrupy.

-phillip