Hi,

I have a Vesuvius and am having a problem I am just struggling to figure out...
A lot of coffee I'm using (blue bottle - subscription) calls for maybe 19 or 20g in the portafilter (double shot, using bottomless double-shot basket)....but whenever I go (much) over 18g I get a bad shot.

Then recently it has gotten worse.
I thought it was my grinder, so just took it apart and messed about a bunch with the grinder...and after testing I think it is doing pretty well.
But now even 18g seems too much and if I drop down to 16g it works "ok" (but no more amazing shots.

I tried to see if the gasket has moved or is in some way messed up, but it seems fine (and was replaced 6mos ago during servicing).

Any ideas/thoughts/recommendations?
Seems to me anything from 17-21g should be fine (rather than my even-previously-narrow range) and yes...the volume would/should be lower with finer grind...but even when near the top of portafilter basket it seems weird that a certain amount of air space (at the top, between top of coffee and the fine filter that sits in grouphead) is absolutely needed - whereas it seems to me like pressure would immediately push the grinds down.

Dunno - but taking to repair place for this will take ~2 weeks and I'd like to learn more myself anyway.

Thanks!! Any Vesuvius owners, or others, for tips.
-J

Vesuvius is a great machine.

Try the dime trick and see how close you are getting to the shower screen.

When was the last time you cleaned the shower screen and group thoroughly by dropping it all down?

Recommendations from Roasters are good but there are too many variables for it to all work out. There is no need for a specific 20gram shot...you should be able to tune for a 14-16 gram without an issue.

What grinder are you using? I'm leaning towards this.

I am curious about the grinder too. The bottomless that comes with the machine won't let me use the VST 20 gram baskets. I have another bottomless that I can use those baskets with so if I am pulling shots with 20-22 grams of coffee I use it. I measure 18.5 grams and my Compak R120 usually gives me 18 grams out. If I am going for a really long preinfusion many times I will drop the dose down to 15 grams and really tighten up the grind.

David