When using OTTO I have created a routine, yesterday morning for some reason the system broke down.
I had done everything the same ……except put water in the reservoir.
I had become accustomed to the sound OTTO makes as its heating and just before the extraction, when I heard a different sound, I suddenly realized what I had done (didn’t do) and dashed to turn off the heat then cooled OTTO down under a running tap.
I opened the reservoir; fortunately it had not gone dry (water left from previous extraction) and the seal of the reservoir cap was fine and the shower screen seal had not been damaged
I was scared I may have damaged some seals or done something irreparable so a few hours later set up for another extraction, and everything was as normal.
There must be good heat tolerances built in to OTTO, but its not something I would recommend others do……
On another matter, for the past 4 weeks I have been weighing my grind, it really allows me to create consistent espresso. Before I was using the level of the porter-filler to gauge the correct amount, but morning coffee and evening were varying in taste and crema. There can be a few millimeter of difference for the same coffee bean & grind depending on the time of day.