I have a 10 gallon system which includes a 15 gallon stainless mash/lauter tun and a 15 gallon boil kettle. When making "big" beers, my mash/lauter tun maxes out at about 34 lbs of grain. I can collect a maximum of 13 gallons of wort in the kettle, which I boil down to 11, before cooling and transferring to the carboys. Yesterday, I used 34 lbs of grain (26# 2-row, 4# munich, and 4# crystal) to make a winter ale. I was happy to get an OG of 1.083, as this is better than my typical efficiency. After collecting the 13 gallons in the kettle, I still had about 7 gallons of wort in the lauter tun. I tested the gravity and found that it was still at about 1.025. So I started wondering, how can I get that sugar into my beer, if my kettle is full up? It occurred to me that I could begin my boil, boil off a gallon or so, and then add more of the wort from my lauter tun to the kettle. I figure that adding two gallons of the "extra" wort in this manner could get me another 50 GU which should bump the OG from 1.083 to 1.088. I'm not sure if the extra hour of time (and propane) is worth it, but has anyone ever tried this approach? Or, better yet, do you have any another ideas (without using adjuncts) for increasing the maximum OG that I can achieve on my system. I realize that I could keep boiling and make less than 10 gallons of beer, or increase my efficiency some other way, but is there another approach?