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Is there such a thing as over efficient?

Well, not necessarily.
I just know I’ve read too many stuck mash stories over the years.
Maybe search some up to identify potential problems before they start?
Usually it winds up with tubing collapsing or not getting a good seal etc.
False bottoms have come a long way and probably work great once you get it dialed in.
Look at it this way,
The worst that could happen is a really, really, really long sparge.

Thanks Scott. Since I’ve confessed to a 10 gallon orange cylinderical cooler, I might as well state for the record I also bought NB’s 12" false bottom. So, is my story getting any better or worse? I have no problems going with SS braid instead if the majority flame false bottoms. Any advice on this?

If you’re batch sparging, then the lauter design doesn’t really matter. Since you have the false bottom, you might as well use it - if nothing else, you might be able to get a faster runoff.

It would have to be an awfully big beer to expect 65% efficiency, though. Make sure that your temperature and pH end up in range, and you should have no trouble getting >90% conversion efficiency. An average-gravity beer with one or two sparges should yield >85% lauter efficiency. So unless it’s a high-gravity mash I’d plan on 75% mash efficiency on the low end. … Efficiency

75% is a pretty average efficiency. I’d base the recipe on that and if you err 5% on either side it won’t be a big miss. Unless your crush is lousy you’ll do better than 65%.

When you run off, if it starts to slow down just rake the top of the grain bed with your spoon, just about in inch into the bed, back and forth in one direction and then the other. It stirs up the fine protein gunk on top of the bed that causes the flow to slow.

Thanks Guys. What if I attempt a thin mash and collect adequate run off w/o a sparge? Here’s my estimate: 13 lbs x 2 qts per = 6.5 gal for mash. Extimate loss of .125/gal leaving 5.7 gal for my boil. Should work out close to 5 g’s upon completion. If I go this route, am I missing wanted/needed sugars that would otherwise be gotten if I were to sparge?
Thanks, Mike

I think you made a typo somewhere. 13 lb will retain about 1.6 gal (apparent), so if you want to get 5.7 gal out you’ll need to infuse 7.3 gal.

Lauter efficiency would be ~65%, low but not terrible. It’s entirely up to you.

Thank you. So what I understand is that some volume of sparge to rinse the grain will or might raise my eff?

should be .125 gal / lb of grain, I think that’s where your miscalc is


I mash in an orange Igloo cooler, with a hose braid, and get 83-85% efficiency on most batches. I’ve gotten up to 90% before but had a stuck mash on that one.

I foolishly started out with a false bottom AND a rotating sparge arm. What the heck was I thinking? Since I switched to batch sparging with a braid (thanks, Denny) and started conditioning my malt (thanks, Kai) I’m able to grind much finer and increase my efficiency. The wort clears a lot faster with the braid - with my false bottom I was always pulling chunks through during the sparge.

FWIW, I’ve only had a stuck mash twice with this setup. The first time was when I cranked my mill just a tad to far, and the second was brewing Jamil’s dry stout, which calls for grinding the roasted barley to dust in a coffee grinder. I think you’ll be just fine. Ditch the false bottom and get busy batch sparging!


If you work through the math, you’ll see that it’s impossible to get such a low efficiency with a moderate gravity beer without incomplete conversion of the starch. Even an unsparged beer should yield better than 65% efficiency, 80-90% would be the expected efficiency from a single batch sparge.

The shape of the cooler doesn’t matter for a batch sparge, as long as it drains fully.

In reading all the posts on this thread, or any thread for that matter, one thing is clear; there are many ways to skin a beer. Another thing stands out as well; we all take our craft seriously and enjoyably and reap sudsy benefits. Thank you for all the great input.

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