That's what I do, fill the canner, fill the water jacket and cover it with my insulation cover. With that running I do other things that always need doing and I check back once in a while until the temperature is at 185-187. I then verify density, draw a grade sample bottle and start bottling. During bottling the cover is off.
Dave Klish, I recently ordered a 2x6 wood fired evaporator from A&A Sheet Metal which I will be converting to oil fired
Now have solar, 2x6 finish pan, 5 bank 7x7 filter press, large water jacketed bottler, and tankless water heater.
Recently bought another Gingerich RO, this one was a 125, but a second membrane was added thus is a 250, like I had.
After running a 2x3, a 2x6, 3x8 tapping from 79 taps up to 1320 all woodfired, now I'm going to a 2x6 oil fired and a 200-425 taps.