hey- i recently did a double, a trappist style belgian with an OG of 1.048. It was an extract brew, done with five 3.3lb cans of extract, about 1.4lbs of grains, 4oz of bitterers, 2oz finishers. Pretty standard. I boiled 6.2 gal for the wort, proceeded through the brew as usual. I ended up with five gal of post- boil wort, so I added 2.5 gal of water to two seperate carboys, and then added half the wort to each. the final yield was 9 gal bottled, and both batches taste great. It is a great idea if you want to buddy up with someone and get a large yield. this is my first post, you guys are all great and homebrewing is the most noble of undertakings. Brew on, gentlemen!