A lot of you out there must brew high gravity beers. For 5 gallon batches, I'm talking ones that can use 15 pounds or more of grain. Doing an all grain batch, and using the values of 1.25 quarts per pound in the mash, and 2 quarts per pound for sparge, you would end up needing 18.75 + 30 quarts, which is a little over 12 gallons. Assuming you lose 2 gallon in grain absorption, you still have a pre-boil volume of 10 gallons. For my set up I lose about 10% of my wort volume per 1/2 hour. which mean i need to boil the wort for over 2 hours to to get it down to the final wort volume that I want. Is there any issue with this long a boil? (assuming you don't add hops until the appropriate boil time, and not at boil start). How you handle even larger OG's (assuming all grain, no sugar added).