Too many variables to say, sorry. I usually felt safe with @ 4-5 brews before refilling. (went to electric so I could brew indoors during the winter and have never gone back)

---Todd

A good question gmh and, for the moment, as thughes mentioned, it's impossible to answer well atm. One of the original aims of the BIABacus has been to provide a structure where things that have never been measured well, if at all, before (like this) can be measured by the individual. Another aim of the BIABacus is to enable an easy collection of numbers based on the many rather than the few.

The next BIABacus Pre-Release has a new section on the second tab where you can use your bathroom scales to measure many critical numbers. A screenshot can be seen in this post. See the right hand column?

People filling in that, over time, will give an answer to your question. The same goes for many other questions.


PP

My brew pot has a built in heat chamber underneath with a flue that runs up the side of the pot. This makes it much more efficient than just running under a standard pot, but due to the fact that the pot is 114L and usually a boil starts with about 60 to 70L of wort I only get about 3 ish brews out of a 20lb bottle.

The burner actually pulls that much gas that the outside bottom of the gas bottle is often covered in a thin layer of ice by the end of the brew.

I get about 8 or 9 hours out of a full 20lb bottle with a Bayou Classic SP10 running just shy of full blast. Figured this out making maple syrup this year, I have noticed as others have said that when you exchange a bottle the new one usually feels lighter than one that I get refilled...