An interesting data point in the vibe vs. rotary pump arena (and there aren't many good comparisons available). Although I'm a big fan of rotary pumps, I've got a lot of respect for Alan's no-nonsense approach to espresso.Alan Frew wrote:Yet another frequently expressed myth is that rotary pumps (as found in commercial espresso machines) produce better espresso than vibration pumps, as used in domestic machines. The arrival of my new laScala Butterfly shipment has allowed me to put this one to rest forever, because along with the Butterflys I imported a couple of laScala Eroica machines. These are identical to the Butterfly except for the rotary pump & motor replacing the tank; they are designed to be the fully plumbed in version. So I set an Eroica and a Butterfly up side by side and started pulling shots. My assistant then moved the shots while my back was turned, and I had to try and pick the differences and which machine produced which shot.
Over a dozen trials I not only couldn't pick which machine produced which shot, I couldn't detect any differences between the shots at all. Pump type appears to have no effect on shot quality whatsoever.