Originally Posted by whodatgeauxbrew
So is there no need to add more water since I am adding more DME? Should we try adding 1 or 2 pounds instead of 3? Does anyone have a good resource for moving to full boil?
The major thing is to stir, stir, stir--especially make sure you're scraping the bottom of the pot with your mash paddle. If any DME sticks to the bottom, it'll burn and create off flavors.
Full boil has 2 adjustments to make:
1. Hops utilization is better (less isoAAs precipitate out, so more stay in the final solution).
2. Chilling is more difficult--the ice water bath method works okay for a 3-gallon boil, but with 5 gallons you have 2 problems: 1) There's a lot more to chill, so it takes longer; and 2) With a partial boil, usually you top off with refrigerated water so you only need to chill to 80F or 85F and it magically drops to the low 60s when you top it off.
To solve (1), use something like http://beercalculus.hopville.com
to enter your hops amounts with the partial boil size, note the IBUs, then switch to a 5 gallon boil and tweak the hops amounts until you get the same IBUs.
To solve(2), you probably want to get a wort chiller (I prefer immersion chillers over CFC/plate chillers, for reasons outlined by Jamil on his site, but plenty of people use the other kinds with no problems).
Otherwise, as long as your heat source is strong enough to get a vigorous boil going it's pretty much the same--start with 6 gallons and you'll boil off about a gallon during the hour. Note how much you wind up with for future reference, so you can adjust that 6 gallons up or down a bit for your setup.