jds
Well-Known Member
Those of us who use brewing software are used to expressing our boil-off rates in terms of percent per hour. Why do we do this? It seems to me that for a given setup, the boil-off rate will be fairly consistent, regardless of the volume under boil.
Example: With my current rig (keggle plus propane burner), I boil off about a gallon and a half in an hour with a vigorous boil. For a 7 gallon initial volume, that's about 22% per hour. But, for the second hour of boil, again boiling off 1.5 gallons, the rate would be nearly 46% per hour.
Similarly, for a 11 gallon batch with a starting volume of 13.5 gallons, the initial boil off rate would have to be set to 19% per hour.
Given that the rate needs to be adjusted for initial volume, why do we do it this way instead of simply expressing boiloff as a volume per hour?
Or am I thinking about this wrong? Anyone? Beersmith, you here?
Example: With my current rig (keggle plus propane burner), I boil off about a gallon and a half in an hour with a vigorous boil. For a 7 gallon initial volume, that's about 22% per hour. But, for the second hour of boil, again boiling off 1.5 gallons, the rate would be nearly 46% per hour.
Similarly, for a 11 gallon batch with a starting volume of 13.5 gallons, the initial boil off rate would have to be set to 19% per hour.
Given that the rate needs to be adjusted for initial volume, why do we do it this way instead of simply expressing boiloff as a volume per hour?
Or am I thinking about this wrong? Anyone? Beersmith, you here?