And here is one of the “mini drip” extractions I was referring to:
The puck was prepared in a very similar to the previous shot yesterday 19.8g of beans before grinding (yesterday it was 20g exactly). Screened out 600 micron boulders and kept the fines (yesterday I also screened out 200 micron fines). Two reasons for keeping the fines today 1) Mostly wanted to see how the fines changed the extraction and the flavour, 2) to compensate for the .2g less beans. Tamping procedure was the same.
Difference in extraction between shots: the one from yesterday required 8+ bar to start, shot today required 0 bar to start. Around 25% of the shots using the Sette are “mini-drip”. The remaining successful shots are quite variable (average quality similar to a low quality commercial espresso machine - but not matching medium quality machine).
Previously when using the manual grinder (before the lock ring “failed”) I had 0% “mini-drips” (1000+ shots?) - and the successful shots were extremely consistent (average quality similar to a high quality commercial espresso machine - but not matching top-end). Obviously after the lock ring started slipping all bets were off…
FYI I tried various sifting experiments with the manual grinder - and everything I tried seemed to reduce the quality of the shots. Which tends to confirm the fact that the Rossa is in some way tuned to match the characteristics of the Rosco grinder.
The machine uses a 58mm La San Marco basket. So I could get an IMS 58mm competition basket (VST do not do 58mm baskets as far as I know).
And the next one was the same (actually worse) first time I ever had two fails in a row - the only thing I can think of is higher humidity 57% today (up from 50% yesterday) - but coffee is hygroscopic so increased humidity usually slows down the extraction
And as they say 3rd times a charm (didn’t sift this one) - so maybe the I will look at increasing the amount of sifted coffee (but that doesn’t explain why the sifted ones I did yesterday worked). So finally a decent shot but not a really great one.
So if anyone has any ideas what I am doing wrong…