[a10t2]

Given plenty of time for complete conversion, a mash out would only improve lauter efficiency.

Assuming 100% conversion before beginning lautering, wouldn't the lauter efficiency depend only on how much water is run off, and in what increments?

[morticaixavier]

Given plenty of time for complete conversion, a mash out would only improve lauter efficiency.

Assuming 100% conversion before beginning lautering, wouldn't the lauter efficiency depend only on how much water is run off, and in what increments?

That's what I have understood to this point. That's why batch sparging results in small loss of efficiency isn't it?

[ccarlson]

Given plenty of time for complete conversion, a mash out would only improve lauter efficiency.

Assuming 100% conversion before beginning lautering, wouldn't the lauter efficiency depend only on how much water is run off, and in what increments?

Well, I think a mash out and sparging with water to keep it just below 170F helps a lot, at least it has in my experience.

As for adding more water, sure you can keep going ( within limits, of course), but after a while you'll spend more time and money on a longer boil than it's probably worth,

[denny]

That's what I have understood to this point. That's why batch sparging results in small loss of efficiency isn't it?

Maybe, but that's hard to imagine after getting 96% mash efficiency on my brew last Sun.

[a10t2]

That's what I have understood to this point. That's why batch sparging results in small loss of efficiency isn't it?

Right. The more you divide up the sparge into smaller and smaller batches, the more thoroughly it's possible to rinse the grain bed. When fly sparging, the number of "batches" is infinite, so efficiency is maximized.

Well, I think a mash out and sparging with water to keep it just below 170F helps a lot, at least it has in my experience.

That's what I was wondering about - once the mash has fully converted, I'm not sure what the mechanism would be that would improve lauter efficiency based on temperature. Kai even did a batch sparge using cold (15°C) water and the efficiency compared to the hot sparge was about the same. It sounds like your results were different, though. Were the batches otherwise identical?

[ccarlson]

Were the batches otherwise identical?

Yes, they were. I've thought about going back to fly sparging, for the reasons you mentioned, but batch sparging is just less trouble with my setup.

[malzig]

Well, I think a mash out and sparging with water to keep it just below 170F helps a lot, at least it has in my experience.

Sure, a 170°F "mashout" can improve efficiency if you haven't reached 100% conversion, but it doesn't seem to matter if you've already achieved 100% conversion at the end of the sparge.

I have pretty much adopted a mash temperature sparge routine and get around the maximum lauter efficiency mathematically possible for the volumes that I use.  I get the same for a 170°F sparge.  I can't really speak to very high gravity beers, where you might expect to see more effect on viscosity, but for normal gravity beers any effect of high temperature is apparently on pushing saccharification to completion.

Isn't that a circular definition?  You get better efficiency because there's better conversion?  What other kind of efficiency is there?

The difference is in getting higher efficiency by improving conversion or by sparging more stringently, which risks adverse effects on flavor.

[tubercle]

Mash, batch sparge, boil.
 
 Ain't got time for the details.

[Kit B]

Mash, batch sparge, boil.
 
 Ain't got time for the details.

Amen...Except, I double batch sparge.

[denny]

Mash, batch sparge, boil.
 
 Ain't got time for the details.

Amen...Except, I double batch sparge.

Then you're wasting time that could be spent on something like drinking! 

[dannyjed]

I don't mash out anymore(thanks to advice from this forum) and I haven't seen any decrease in efficiency.

[Beer Monger]

I've never mashed out.  It's difficult when your mash tun is a cooler.  The only way to raise the temp is to add more hot water. 

Not mashing out has never seemed to be a problem for me.  I'll have to try batch sparging at some point, though, see how much time I can save in my brew day.   

[malzig]

The only way to raise the temp is to add more hot water.

Not the only way.  If you really want to do a mashout, you can draw off some wort, heat it to a boil and add that back.  I never use decoctions to add flavor, but I often use them (without an etended boil) to raise the temperature of my mash.

[Beer Monger]

The only way to raise the temp is to add more hot water.

Not the only way.  If you really want to do a mashout, you can draw off some wort, heat it to a boil and add that back.  I never use decoctions to add flavor, but I often use them (without an etended boil) to raise the temperature of my mash.

True... but I just don't bother. 

[SpanishCastleAle]

I agree. Given plenty of time for complete conversion, a mash out would only improve lauter efficiency. I always go at least 90 minutes for mash time, but more often I go 2 hours. After that seems to be diminishing returns.

When I read the OP the first thing I thought was that after a 90 min mash @ 150* F, a mash-out wouldn't make that much difference.  I often mash for much shorter times (like 45 min but only when mashing at higher temps) and in that case I see a fementability difference...no mash-out = more fermentability for that given mash.  I fly-sparge...if at all.

Recently I've been reducing my sparge volume more and more (to the point of no-sparge) and surprisingly have not suffered much loss in efficiency.  So these days I'm mashing REALLY thin and only sparging a gallon or two and still getting ~73% brewhouse efficiency.  I had it up to 92% at one point but intentionally dialed it back, there were a few over-sparged batches in there.