I had some issues with water volumes for brewing the Winter Warmer (pdf)
. I reached the 60 minute mark, and after removing the hop spider (and ensure all liquids were drained out of the spider), I had about 6 gallons remaining, when I had been shooting for 5.25 to 5.5.
So, I turned the burner back on, and boiled for an additional 20 minutes, without the hops in the kettle. I know I should have done this on the front end; that said, what can I expect?