Philosophy: When is a "lever" no longer a "lever"? - Page 2

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#11: Post by Pressino »

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." 8)

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#12: Post by another_jim »

Pressino wrote:I guess that would be more of a spandrel rather than "pre-adaptation." 8)
That's mostly above my biology knowledge paygrade.

But for me, going to a lever was not about a practical mechanism becoming decorative and iconic No doubt, lever machines says "espresso" better than anything else; and many long established hobbyists collect and use levers machines for this reason. But the current revival, I think, is more about the pressure profile as it applies to light roasted coffee. That takes a mechanism designed to be cheap and easy to maintain in a low tech commercial setting making low cost coffee, and places it in an affluent hobbyist home for making high end coffees.
Jim Schulman

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#13: Post by mrgnomer »

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.
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professionals do it for the pay, amateurs do it for the love

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#14: Post by ira »

The Meticulous does not need a lever other than it improves the packaging. It could easily have the actuator above the piston and accomplish the same thing with no lever, or replaced the lever with a belt and a couple of gears like Duvall and Unica do.

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#15: Post by baldheadracing »

Jeff wrote:When does a lever machine cease being a lever machine and just become a pressure-profiled pump machine?
When a pump supplies the pressure used throughout the extraction.
-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada

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#16: Post by drgary »

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.

What I WOULD do for a good cup of coffee!


#17: Post by jpender »

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?


#18: Post by Primacog »

espressotime wrote:I use the definition of Reiss of Londinium Espressomachines.
He was spot on.
A machine that uses a pump to bring water in the group isn't a lever machine.
It is a pumpmachine that uses the lever as festive decoration. Therefore the only levermachine Londinium makes is the Vectis. The other ones are pumpmachines/hybrid machines.
And he is right. Since preinfusion is part of the extraction.
An espressomachine with a pump inside to me is a hybrid. Half pump,half lever.
Anything without a pump is a levermachine.
I dont quite understand that definition. In what way does the lever mechanism itself fill the group with water? Doesn't pulling down the lever only open the valve that allows water to flow from the boiler into the grouphead, and then it trickles passively through the screen onto the puck to preinfuse? The spring and the lever mechanism (the lever and fulcrum) itself have not become active yet at that point. Hence the machine hasn't begun to act as a leve reaching yet at that point. They only become active when the lever is released and the springs then begin to drive the lever mechanism and this is when extraction begins.

If that's the case, then the defining characteristic of a lever machine is that it uses a lever mechanism to drive the extraciron process and that definition would capture the r24 as well as the hybrid levers and traditional spring and manual levers too.
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#19: Post by another_jim »

espressotime wrote:.. A machine that uses a pump to bring water in the group isn't a lever machine.
Anything without a pump is a levermachine.
If you fill the boiler via the mains, you are using a pump to fill it. The pump is run by the water board, but it is still a pump. If the same water mains sends water through an HX, it is filling the group as well. By this defintion, the only lever machine is dipper with a pour in fill.

Olympia, Elektra, La Pavoni (but not the Pub), and Odyssey will be delighted by this defintion. Commercial machines, including the orignal Gaggia, need not apply.

Oh wait a minute, the water you are pounring into the boiler, did it come from a tap?
Jim Schulman

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#20: Post by baldheadracing »

Primacog wrote:I dont quite understand that definition. In what way does the lever mechanism itself fill the group with water? ...
I think that you might be missing the historical references that provide the humour/sarcasm of the post.

But yes, <Jeremy Clarkson mode on>Some Say that a lever machine has no pump.<Jeremy Clarkson mode off> To answer your question, the group is filled by either gravity (open boiler), or boiler pressure (dipper), or line pressure (HX). Use of a pump to fill the group (in the machine, Jim) means that the machine is a hybrid of a pump and a lever. A mule is a hybrid of a donkey and a horse. A mule is not a horse, nor is it a donkey. A mule is its own thing, just as a "hybrid lever" is neither a lever machine nor a pump machine, but a combination of both.

The above paragraph is more humour. I happily call my Strega a lever machine.
-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada