> There is a pressure seal directly in the group head that holds the water in at the end of a shot.
Like a check valve? Does that mean that some (clean) water is trapped between the pump's output and the seal at the end of the shot? If so, this doesn't seem so terrible.
One thing I've often found odd about espresso machines is that they all seem to have some mechanism to depressurize the basket when a shot ends, and that this mechanism lets water that may have been in contact with the grounds go through some portion of the machine. What's the point? The pressure will naturally dissipate quite quickly through the grounds unless like kind of pressure-retaining basket is in use.
Basically it removes excess water from the filter, creating less soggy pucks. Easier to clean. I imagine the rapid depressurisation "upwards" may cause the puck to move a bit upwards, again, making it easier to remove.
Like a check valve? Does that mean that some (clean) water is trapped between the pump's output and the seal at the end of the shot? If so, this doesn't seem so terrible.
One thing I've often found odd about espresso machines is that they all seem to have some mechanism to depressurize the basket when a shot ends, and that this mechanism lets water that may have been in contact with the grounds go through some portion of the machine. What's the point? The pressure will naturally dissipate quite quickly through the grounds unless like kind of pressure-retaining basket is in use.