Actually, I'm still trying to get it down... I've always fly sparged. Probably batched once in the last 6 years. But now I own a homebrew shop, and 95 percent of my all-grain customers use a converted cooler. It's an inexpensive way to mash, and people say it works well, so I made a basic Igloo Ice Cube 60 qt mash tun, with a drilled CPVC manifold and have had nothing but problems with it.

The first time i used it, we got busy at the shop and somehow i only mashed half my grain (don't ask me how that happened). I ended up doing two mashes and ended up with 65% efficiency, but since i had such a weird mashing situation i wrote that one off as user error.

The second time i got all my grain in (yeah!), but ended up overestimating my sparge water. Now, with fly sparging that doesn't matter a bit. You just stop the flow, and run the rest down the drain. When I batch sparged this time i sparged twice, but put too much in the second time and didn't run it off. I'm assuming that's why i ended up 60% efficient.

What do i need to do next time to get up to a respectable efficiency? A customer remarked that i should drill more holes in my manifold, but in my mind that doesn't compute. In batch sparging channeling is not an issue, right?

Do you batch superstars sparge once or twice? What am i missing here?

Check out Denny's site . I follow it and only do one sparge but you need to add extra water to the initial mash to equal half of the boil volume then add the other half as the sparge.

I drain completely, add half my sparge water & drain, then add the other half & drain once more. Make sure you are stirring the mash after each addition. You may want to increase the temperature of your sparge water to keep the grain bed temp in the upper 160's, after I started paying more attention to this my efficiency went up to 85% for an average strength beer.

I always batch sparge. Instead of draining directly into the boil kettle, I drain the tun into a bucket that I have marked every 1/2 gallon. This tells me exactly how much sparge water I need to add. I hit my preboil volume every time this way. I use a stainless steel braid loop hooked to a tee fitting that fits into the bulkhead fitting on the mash tun wall. I normally get 75-80% efficiency with this system.

Targeting half your desired preboil volume from your initial infusion of strike water maximizes your efficiency while minimizing the chance of astringency. Figuring this is pretty easy. The first thing to do is figure out the dead space in your mash tun (the amount of wort left in the tun once anything stops flowing out. Just put some water in there, drain it out like you would when brewing. Pour the remaining water into a measuring pitcher. Write down this volume somewhere, you will use it every time you use that mash tun. On brew day, figure out what half your preboil volume is going to be. Lets say you want 7 gallons preboil. Half will be 3.5 gallons. To that you add one pint of water per pound of grain. For a 12 pound grist bill you would need 12 pints or 1.5 gallons. To this you add the dead space volume, for this example lets say that it is 0.5 gallons. 3.5 + 1.5 + 0.5 = 5.5 gallons of strike water needed to dough in. This is a mash thickness of about 1.8 qt/lb which is right in the target range of 1.5 -2.0 qt/lb that I shoot for.

This is how I figure mine but your mileage may vary.

Wayne

When I batch sparged, I would add some boiling water to reach half my preboil volume and help with mash out. Vorlauf, then drain the MT. Next add the other half of my water to the MT, vorlauf and then drain to kettle. You should at least get 70% eff. If you are not, you probably have to crush your grain a little smaller.

Yep, yep yep, Denny's site is great, I use a hose braid as well and works great. I use a rectangular Coleman Extreme Cooler that has a channel in the bottom that helps get every last bit of wort out. I used to use the round Rubbermaid and that left quite a bit of wort left.
Yep Yep yep yep.

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?

There's a batch sparge calculator here that I've used for years to hit my temps and volumes nearly every time. The cool thing about batch sparging is that after the initial drain, the grains in the mashtun have already soaked up all the liquid they're going to. So measure how much wort you have in the kettle after the initial draining, subtract that from your target pre-boil volume, and that's how much sparge water you add. Everything you put in, you get back out, volume-wise. Once you know this, you should always hit your pre-boil volume exactly. For the best efficiency, you want to collect half your wort in the first drain, and half in the second. That's where the calculator will help. It even has a provision for mash-out. (I also preheat my mash tun and set the thermal loss thing to zero. I set grain absorption to .15).