slanted & enchanted wrote:
Do you batch superstars sparge once or twice? What am i missing here?
Warning: I'm long-winded and have thought a lot about this very thing. Of course, I'm not the best brewer in the world and I'm not nearly as educated in the behavior of sugars/starches/grains in a liquid as I'd like to be so you can't take my word as any sort of authority. This is all hypothesizing but might lead to discussion/input from those much smarter than I.
I'm sparging once because I get my entire volume out of my first runnings and my single sparge. Theoretically you could (by doing two sparges) collect your first runnings (with the required stir, rest, vorlauf, drain), do a small-ish infusion of water, stir, rest, vorlauf, drain, then do another infusion of sparge water, stir, rest, vorlauf, and drain to get your boil volume.
When I used a smaller mash tun than I should have been using, I had to sparge twice a couple times (I couldn't fit enough water in the damn thing to get my volume from the first runnings and single sparge). That's the only reason I would sparge twice (unless I wanted to partigyle).
My worry would be that the entire third dilution (second sparge) of the mash would be too low of a gravity and you'd get an entire third batch of runnings that you wouldn't want to use because of tannin extraction (forcing you to add water instead of runnings to the boil kettle).
These numbers are all made up but useful for explaining my thought process on the drawbacks of a second sparge. Again, these ARE NOT measured-and-tested real-word examples but ARE useful in illustrating my point.
Let's say that you're mashing x lbs of grain hoping to get 10 gallons of liquid in the kettle pre-boil. X lbs of grain could give you 4 gallons of 1.060 first runnings. Well, you've extracted a lot of good sugars from the grain. Now you throw in your first batch of sparge water, stir, rest, and drain. Taking a gravity reading gives you 4 more gallons of second runnings with a gravity of 1.024. So, not getting enough volume, you do another batch of water with another stir, rest, and drain step. This time you drain out 2 gallons of whatever water you threw in at a gravity of 1.009. I worry that that's getting into tannin-extraction territory (a lot of brewers much smarter than I claim 1.010 as the gravity at which you'll start extracting tannins from your grist).
Conversely, a second mash could be done (assuming a similar amount of sugars available) but with only one sparge - draining 4 gallons of first runnings at 1.060 and 6 gallons of sparge at 1.015~1.017. You're not getting close to the 1.010 line a lot of brewers claim as the threshold for tannin extraction. Hell, you could run off 8 gallons of sparge liquid instead of six and, assuming you're pulling the same amount of sugars out, not get below 1.010.
Maybe I'm completely off-base and waaaaay wrong, but it helps me sleep with my beer at night. Anyone have any thoughts on these thought processes?