How long should it take to get a decent rolling boil on the G70?
It should take 40-60 minutes from sparging.
A tip is to switch the G70 to 99°C (210°F) while you are doing the sparge to speed up the time it takes to get to the boil.
By the time you finish the sparge, the G70 should be close to temperature.
Note: This is automatically done when using a managed brew session in the app.