Fly Sparging

Im looking into making a nice big RIS. My brew tool says that prettymuch all the water will be for the mash and a few quarts for the sparge. With a high gravity brew like this do people still fly sparge? im guessing its prettymuch a batch sparge at that point.

Batch sparge wouldn't help you in this situation. I'd rather add another pound or two of grain and no sparge if all your going to be doing is adding a few quarts.

Your tool is probably basing the water quantities on your target pre-boil volume. For a big RIS, you're going to leave a ton of sugars in the mash with that small of a sparge volume. You could add some more grain and do a partygyle. What I do for a big RIS (or any really big beer) is load up my HLT with a good amount of sparge water (I usually heat up 8-10 gallons regardless as is doesn't hurt to have too much), I'll sparge until I get a desired pre-boil volume (more than i normally would have and boil down) or until the runnings are at you're desired gravity (Typically 1.010). Since my system is set up to run from the MT directly to the BK, I don't typically test the gravity. I also know how much pre-boil wort I need to hit a certain gravity based on boil off (at least for my system). So for a 5 gallon batch of, lets say 1.100 OG wort, I woud shoot for a pre-boil volume of about 10 gallons (I'd have to check my notes at home to be sure), assuming no added sugars in the boil. I'd then boil down to 7 gallons, test gravity, and add my 60 minute hop addition, continuing as normal. By starting with more wort and boiling down, you're concentrating the sugars which will allow you to hit your high OG. Others may do things differently, however.

I did a Russian Imperial Stout with 22.75 lbs of grain for 5.25 of wort, managed to get 76% efficiency.

Mash water was 24.82 quarts. Sparge water was 3.75 gallons.

I did take an unusually long time (almost 2 hours) to sparge including a 30 minute break (I was doing 2 batches).

90 minute boil.

I ended up with 1.114 OG.

MC