The second-pull dynamic is indirectly relevant to the issue of shot volume, even to "single pull volume", if single-pull includes preinfusion partial-pull(s). I would certainly recommend that it include them.

As per Timo's suggestion I covered the porta filter holes on my PVE with my finger. Doing this while the porta filter was still warm to touch while the machine was heating up.

Air escapes between the top of the porta filter rim and underneath the rim of the basket!

It is possible that the leakage at this gap is reduced when the machine is hot. But until further testing my bubble theory is "on hold".

Geoffrey

Red West

Sorry that this thread has diverged from your original question.

To help answer it. From my Ponte Vecchio Export with 2 gm of coffee in a double filter basket and with 2 pulls I repeatedly get 2 ounces of espresso. This volume includes crema and some pre-infusion flow.

If the grind is correct and the speed of the piston on both upstrokes is really slow typically I do not have any problems with puck fracture or fissures because of the second pull . This is verified by the appearance of the used puck.

This does not mean I do not have problems. I do. But, mostly when changing to a new coffee and before I have "dialed in" the grinder.

Hope this helps
Geoffrey

Hi,

I'm glad for all the thread comments, it seems volume is just one small part of the story.

I went ahead and acquired a La Pavoni Europiccola for my first machine.
The grinder I bought had a defect, so still waiting for a replacement before taking the first pull.

Anyway, thanks for all the advice, I'm sure I'll be asking for more as time goes.

Red

Red West

I went ahead and acquired a La Pavoni Europiccola for my first machine.

Congratulations!