another_jim wrote:
In evolutionary biology, there is a concept called "preadapation," when some feature that was useful in one minor context suddenly becomes the next big thing when the species evolves into new lives. Feathers, used by dinosaurs for insulation for tens of millions of yearrs, becoming useful for flying, is the standard example.

In espresso machines, we've had two very striking cases of preadapation. First, the spring lever profile as applied to lighter roasts. Second, the needle valve inthe E61, present in the patent design, and briefly used for flushing the group, suddenly getting a much more glorious second life as a pressure profiling controller.

So, when is a bird no longer a dinosaur?

This evolutionary analogy in understanding the morphing of lever machines is fascinating. As you probably know, Stephen Jay Gould used evolutionary analogies to explain such non-biologic phenomena as the diminishing size of Hershey Bars. In the case of the "evolving" lever machine, I wonder whether certain phenotypic features (like the hand actuated lever itself) would more accurately be described as spandrels or pre-adaptations. I guess it would come down to exactly how their functional roles changed over time.

For example, the manual lever arm was designed to make it easy for the operator to compress the group chamber piston, either directly or indirectly via springs. The lever arm itself was not essential, as the piston could have been compressed by other means, such as an array of gears driven by an electric motor. In that case the machine's group would function essentially the same as a manually operated lever machine, but "purists" would almost certainly quibble about that. Noting such grumbling from lever purists, manufacturers probably would try to recapture that market by adding an almost totally unecessary (and essentially decorative) and prominently displayed lever that does nothing but serve as a switch to activate the electromechanical piston assembly...

I guess that would be more of a spandrel rather than "pre-adaptation."

Is a dual clutch transmission with paddle control still considered a manual? Technically, I think, yes. Practically, no.

The thing I like about stick shift clutch pedal standard is the same thing I like about lever driven piston machines: direct control. The Strega hybrid I like because it uses a HX, a heated group and pump assist to add lever control options. Sure, you can use the pump for full extraction but you can bypass it too for pumpless preinfusion and spring pressure piston extraction control. Stopping the lever return in the middle of an extraction is like putting a transmission in neutral. That's hands on control which, to me, is what lever piston machines offer.

I guess it's technically still a lever if the piston is robotically controlled but the loss of mechanical direct control is a disadvantage not an advantage, IMHO.

To me, it's not a lever machine unless you can grab a lever and move it to control a piston pushing coffee through the brew chamber.

Suppose the lever were in your kitchen connected via the internet to a machine a thousand miles away that responded precisely to the pressure and movements you made. Lever or not?