I've been told that the typical o-rings that one buys for the Europiccola are EPDM, but I don't have proof of that. A few years is what I get from them. Will be interesting to see how well silicone on the cap holds up to frequent movement

I got tired of cheap EPDM o-rings hardening, so I just replaced the boiler knob o-ring with 36mm OD x 3.5mm silicone and the group-to-boiler o-ring with a 34mm OD x 3mm silicone. Both are available on ebay. Fit seems perfect

I just brought 5 lbs back from Volcan. Very nice for espresso - but yes, less pungent than most

Re temperature effects: also the temperature of the grounds before brew. And air temperature and air flow (because it effects the delta between the surface temperature of the group and the interior temperature)

The ebay model looks like a very cheap clone. Given that it's a resistive load, I would think that any high quality, certification marked, name brand 20A SPDT toggle switch would be fine. But about 4x the price. For example, an Eaton XTD2B2A or XTD2B1A. Or even 15A is more than needed

IMO, it would be more correct to say that the pressure and puck depth you choose to use requires a coarser grind. I use the same grind as a 58mm pump driven machine (with a decreasing pressure profile)

You want both switches on for warmup and you want both switches on ~20 seconds before lifting the lever. But I still use some micro pumps (until firm). Don't flush (makes the group too hot) or purge air (not needed, using both switches, this model air purges itself). I dose at 11.6 grams. At the beg...

IMO, a pressure-stat would be a downgrade. If you can't fix it, consider going to PID so you don't have to worry about false pressure/air bleeding or hysteresis. The escaping steam in the two switch models is also useful as an audible "almost ready to brew" alarm - as rpavlis says, you want to brew ...

See my signature for an earlier example of "smarter than PID*" temperature control. Note that while repeat-ability is always a good thing, maintaining a flat temperature while brewing often isn't (I prefer a decreasing temp). A small boiler combined with smart temperature control can be used to crea...

If anyone wants a range to consider for best dose, one way is to look at equivalent puck depths people have used in 58mm baskets. For example, 20g in a 58mm basket is about the same depth as 14.3g in a 49mm (multiply by .71). Adjust the water volume in the same way. Using this