What does the pressure gauge on the Rocket Appartamento read? The pressure gauge on the Rocket Appartamento tells you the pressure of the boiler. It does not tell you the pressure while brewing. So you can use that pressure to know when your machine is ready for use and you can use it to know when your machine is ready to steam. If the pressure gauges is in the green area you know that the temperature is high enough to pull your shots and you know it's at the proper temperature for steaming. But you can’t use that to determine your brew pressure. If you want a machine that reads brew pressure, you need to get something like the Rocket Mozzafiato Type V.