My Millenium La Pavoni Pro has started to pull out of one spout only after *years* of working perfectly. Alright, when I was first starting out with this it did pull on one side only, but I attributed it to the grind, the tamp, and the beans. For quite a while now, no blow-holes.

Fast forward to a month or so ago... More often than not, I am now getting espresso coming out of one spout only. I've kept the grind level basically the same, only adjusting it as the beans age. Also, the beans have been from the same roaster for longer than the problem has existed. And the tamping has been the same, although I don't have any way to measure the actual tamping pressure.

So... has something changed or worn out internally with the piston perhaps? I vary between a 5- and 10-second pre-infusion depending on the age of the beans, but I haven't noticed any correlation between the pre-infusion and which spout the espresso comes out of. Oh, it's *always* the right-hand spout.

The flavor isn't sour or bitter, so I'm thinking that there is no blow-through; however, I'm no expert. I just have noticed a change in operation.

Does a dummy shot flow equally from both spouts?
I'd start by removing the basket and cleaning with a brush and detergent to see if that changes anything for you.

Crack the GH bolts loose, place a spirit level against the underside of the GH (sans PF) to level, then retighten bolts and verify that it's still level.

Better still, remove the screen and water spreader and level against the group face. The outside bell may not be true to the machined group face.

Use something like this



and calibrated with a known true level

OR

Use a true spacer to measure the group face and verify it is true with the PF bell.

Crack the GH bolts loose, place a spirit level against the underside of the GH (sans PF) to level, then retighten bolts and verify that it's still level.

Well, it seems the GH is not level. Tilts ever-so-slightly to the right (looking from the front). This might explain why it has always favored the right-hand spout. It's not enough tilt to force all output to the right-hand spout, though. Could an uneven tamp cause this? I sometimes don't push straight down.

Use your fingers to ensure the tamper is even.

The likelihood that you always tamp to favor the right is small.

lmolter wrote:Well, it seems the GH is not level. Tilts ever-so-slightly to the right (looking from the front). This might explain why it has always favored the right-hand spout. It's not enough tilt to force all output to the right-hand spout, though. Could an uneven tamp cause this? I sometimes don't push straight down.

Perhaps. Sometimes the silliest things can make a difference.
Try tamping with your other hand. #angleofattack