Temperature stability La Pavoni Millennium Vs pre Millennium + thermal insulator gasket kit 

plastic sleeve. I don't remember which type was the piston. In general, metal will add thermal inertia, so it will be harder to cool down.

@@Giop Even though the Millenium is supposed to be a better thermal design, I find that it just sucks I have never had any decent coffee with the Millenium - nor would I waste good coffee on it. Having said that, I never had the right grind with the coffee I used with the Millenium - always used pre-ground supermarket varieties which are invariably too coarse for LaPavoni Europiccolas/Professionals. The pre-millenium Professional though, can produce fairly decent shots even with those pre-ground varieties.

​@@Stelios.Posantzis My guess is because the pre-mill has a smaller diameter basket, easier to use with a coarse grind size (thicker coffee puck, less channeling). Temperature is different, maybe you use the pre-mill at a better temp than the mill, leading to a better extraction. To master the temperature, a thermometer is needed. First of all. don't use pre-groud. The correct grind size is somewhat one of the central problems in making an espresso. It must be right, otherwise the high pressure extraction process will not happen correctly, giving odd taste. That said, the temperature is another important thing to master. With correct grind size and temperature control, the millennium can make good coffee

@@Giop These are my conclusions too. The Millenium essily overheats and also can cool down very quickly, e.g. between shots, so it's hard to get it to a stable, desired temperature. The combination of pre-ground coffee and high temperature makes for lousy shots. I will experiment with grinding coffee for the Millenium but the high temperature problem I do not have high hopes for. With the pre-Millenium on the other hand, I do not need a temperature meter: I can tell when the right temperature is reached simply by having the same water level every time and pulling a shot at the exact same time after turning it on - which isn't long. I can tell if it's too hot when the head feels too hot to touch. For me, the pre-Millenium, with all its imperfections is, somewhat inexplicably, the better machine.

for espresso only, you don't need steam power, so you can lower the pressure and have a little bit cooler water temp in the boiler. It helps to reduce overheating issue. Preinfusion will be a little more weak, but you can help doing mini pumps until you get first drops.

@@Giop that's right my friend I tried some days ago 0.8 max setting and i saw that there were less water in the chamber from 1.0 bar setting That's why I return to 1.0 bar, but i still doing tests, with various group temperature etc I don't have problem to do Fellini moves, if i will gain the better espresso performance

@@wakeawaken430 it depends if you have a problem with too much high extraction temperature. If it's not a problem for you, an higher pressure for sure will help you to push more easily water into the puck during preinfusion. But i think you can overcome this by doing the necessary felllini moves. I don't suggest to go down more than 0.8, it becomes too weak pressure.

@@Giop thank you again The logic says that i can lower the water temperature in the boiler(pressure 0.8) and try a little higher group temperature, for the same final extraction temperature For example, 120°C water temperature (1.0 bar) with 85°C group temperature, and 117°C water temperature (0.8 bar) with 88°C group temperature The only thing that i don't know is if then i will have a declining water temperature profile If it's not too big, it's not bad