Danno, yes, there is a distinction between the first few shots and subsequent shots.danno wrote:I think the fact that multiple shots was mentioned leads me to believe that the Cremina can be left on for extended periods of time. This subject has been visited before. Leaving it on all day is probably a bad idea, but since the machine turns itself on and off as needed to maintain pressure, leaving it on for several hours seems entirely reasonable. Drawing several shots at a party, for example, would be well within the parameters of the machine's design.
Best wishes in the new year!
The most obvious way to heat the grouphead and portafilter are by flushing before pulling your first shot, and by pulling subsequent shots. The grouphead and portafilter get hotter and hotter until they presumably reach a max temp which is probably too hot for ideal shots. At that point a cold portafilter might help a bit but I'm not sure it would make enough of a difference to prevent the burnt crema of a too hot shot.
Now if you leave the Cremina on without flushing or pulling shots, or after pulling only one or two shots, presumably it would reach the same max temp - or would it? My recollection and experience say an idle machine can/will get too hot, but I've never tested systematically. And it wouldn't be high on my list of things to test, or that Steve should test. Since the machine comes up to operating temp so quickly, and since the boiler may need to be refilled anyway for many more shots, there is really no reason to leave it on for extended periods, even when you know you're going to be pulling shots in close proximity. I used to leave mine on from wakeup drink through mid morning coffee break, and sometimes even through lunch if the water level were not too low, but I don't do that anymore. There are always too many things to do in the kitchen anyway for the 10 minutes it takes a cold Cremina to heat up and be shot ready. At least my wife is happier that I spend some time cleaning some of the mess I make.