FWIW my experience is that the Bacchi successfully brews a wide range of coffees at its default setting. I am all for experimenting (although there would be no way of using a Scace on a Bacchi if you had one), but I think the product is optimized where it is and should not be "over thought."

True, the Bacchi comes set to brew good espresso, particularly if your heat source gets it up to a whistle in 6 minutes or so. In that case, you are absolutely right - don't give it a second thought.

However, depending on where I am, I don't always have the same heat source and sometimes the process takes longer than 7 minutes. Others may be in this situation as well. Doug from orphanespresso suggested that the Bacchi can be adjusted to whistle sooner, so it might be worth a try.

Giving a 1/4 turn twist inwards to the middle valve, for example, could get the desired 6 minute whistle, and in that circumstance it would be good to know how this affects the shot in terms of pressure and temperature.

This is obviously not easy to measure but even a few general thoughts about the possible effects of these adjustments might be useful at this point. Or, if anyone has tried this, let us know what's happened so far.

Dom