I'm a newbie to the Europiccola. I've been using it for a few months and I'm just starting to get good shots regularly.

For such a simple machine it's confusing because of all the inter-related variables (some that don't really need to be inter-related) such as boiler pressure controlling brew temperature, when the only function of boiler pressure (when not steaming) is just to push water up the siphon tube and into the group head; and independent variables like the fact that boiler pressure has nothing to do with extraction pressure from the lever.

Then there are the mysterious design "features" - like the thermal mass of the group head functioning to initally cool the brew water, but after a few shots the thermal mass works against you and it makes the brew water too hot. I suppose its classic Italian Design; beautiful, over engineered for durability, under engineered for reliability/consistency. What would this classic look like it was designed by a Japanese company like Shimano or a German company like Zeiss or BMW? But I digress.. (too much espresso).

Here is my latest Europicco-physics conundrum: why is there air in the brew chamber: aka squishy lever.

[*]You lift the lever.
[*]Water rushes into the brew chamber under pressure from the boiler.
[*]After you feel the water rush into the group head the lever is squishy and by pumping it up and down 2-3 times you push the air above the water back into the head space of the boiler. Once the brew chamber is flooded the only way out is the top hole in the boiler-to-group head connector (there are two sets of holes: lower holes to let water into the group head from the siphon tube and an upper hole to let air go back to the head space of the boiler).

Wouldn't it have made more sense to have a one-way valve on the top of the group head to let the air out so the brew chamber can fill completely with water? Is this pumping out the air of the brew chamber really the best they could come up with? Am I missing something obvious here or doing something wrong?

I've also noticed that the "squishy" lever (air in the brew chamber) happens more on the first shot than the second. I don't really have an explanation for this except that maybe the temperature and pressure are so great on the first pull that the water is flash boiling up the siphon tube which creates more steam.

I'm interested to hear any and all caffeinated theories.

I lift the lever, wait 5 or 10 seconds, and pull, no multiple/felini pulls.

I notice I only get the mushy lever when I dont have enough pressure (boiler pressure)

My theory is without enough boiler pressure you arent getting the maximum pre-infusion and still have some air trapped in the group head. Most if not all of the air should get forced out thru the puck during pre-infusion. If not you will get a nice foamy air infused shot.

The top hole in the group head (my theory again) not only gives a littel "boost" to the boiler pressure when you raise the handle, but also you can tell when the pre-infusion is ready because the handle will stay in the up position, the pressure is equalized between the top and bottom of the piston... both being at the boiler pressure.

Now Im no expert but I know that there are a lot of variables in the lever technique and as long as the end result comes out to your liking its tough to argue that its right or wrong.

And I for one am always looking for any other techniques to try and incorporate into my own

javaman wrote:I've also noticed that the "squishy" lever (air in the brew chamber) happens more on the first shot than the second. I don't really have an explanation for this except that maybe the temperature and pressure are so great on the first pull that the water is flash boiling up the siphon tube which creates more steam.

Perusing this thread will help answer your question: Second pull is harder?

Jon