so for this customer we only sold him the group so he could upgrade an older machine; this is his story:
Here’s a bit of evaluation. I’m comparing the output of my machine to the way it was with the original bezzera lever group. (It’s old, much older than the Strega, but looks very similar if not identical to the Strega’s group.)
With the old group there was always some injustice going on in the cup. Only rarely did I get the taste I was after. On the rare occasions that I did, it seemed more luck than skill. Often harsh and a bit sour, even when using beans that really shouldn’t have much acidity. So I ended up making milky drinks most of the time.
Damn, what a difference a lever group makes… With the new group it’s right on the money. Every single time.
Surely the Bezzera engineers did a very decent job on the thermal design of the machine. Measuring with a rapid-reaction, high-precision, ultra-thin probe inside the puck the temperature is always nearly perfectly flat (down to 0.1 degrees) during extraction (assuming a proper pre-infusion). (Yes, it messes up the extraction a fair bit, but it’s nice to know the temperature profile during extraction at the point of extraction.) But that didn’t change with the recent makeover.
Somehow the new group delivers the output much better. I’m getting silky smooth, rich, gentle and full-bodied espressos.
The paraphernalia I bought in the Londinium store recently (distribution thingy with funnel and the slightly deeper IMS baskets) help. The odd channeling shot that I experienced when I first started using the new group (much less often already than with the old Bezzera group) are now eliminated. Haven’t had one of those since. Kudos on the thingy’s design (and on deciding to make it in the first place).
Also, the Bezzera group had mechanical problems. Don’t know how it happened, but over time the piston rod would get bent. Not in the middle, but where the thick part transitions to the thread on the side of the lever. Never quite figured out how this happened. Longer ago I blamed the odd jaw-breaker manoeuvre (accidentally letting go of the lever without a loaded portafilter being in place). But the piston rod somehow always ended up scraping the sides of the hole in the guiding part on the top of the group, chafing off brass dust that ended up in the top the group. The new group is a different story. Such smooth action.
I won’t use the additional spring anytime soon. In the single spring setup the new group already requires a fair bit of additional force compared to the old one. Clearly the machine wasn’t designed to deal with that. It requires a special, gentle pulling technique to prevent the machine from toppling over forward. But with some minor practice it’s perfectly possible to pull the lever down while keeping the machine on all-fours. (Without having to push the front plate backward with my other hand.) I’d have to weigh the backside of the frame down with a block of tungsten or nail it down to the counter or something if I ever add the second spring.
So in summarising it’s fair to say that I’m very happy with the makeover. Very happy indeed. Thanks again for helping out.