Sounds silly when you first read the question, kind of like the question "Who's buried in Grant's Tomb?" I'm doing my first full extract 5 gallon boil. I have 7.5 gallon kettle and a 210k BTU burner. I don't know the loss rate during the boil, therefore, not sure if I should start with 6 gals or more. Issue is if I finish the boil and have more than 5 gals remaining, won't that effect the flavor since the extract was made for a 5 gallon batch?