Consistently low efficiency

I've been an avid homebrewer for over 8 years now and made the jump to all grain last year. I've upgraded most of my equipment and purchased a 40qt rectangular cooler with custom manifold, crankandstein 3E, pH meter, and 2 temperature probes.

I've consistently only received around 58-62% efficiency for any recipe. An example of a recipe is listed below.

5 gallon batch size
Single infusion
14.5 lbs grain bill
18.13 qts of water for mash-in (1.25:1 ratio)
11.8 qts of water for fly sparge


The rectangular manifold was designed with input from the How To Brew book regarding spacing between the sides and number of runs to the drain. It's all copper and connects via silicon hose to the output.

My temperature has always been within 1° to 2° of target and the pH has always been 5.2 or 5.3 without the use of any buffers. I've measured the gap in the grain mill and it is about .045".

Any ideas would be greatly appreciated.

Do you have a picture of your crush? .045 gap could be your problem.

Are you stirring really well after adding grain? Dough balls, break up starches.

Are you sure you're not getting channeling? Try a batch sparge with a lot of stirring.

Crush seems to be the most obvious. I'd tighten and see if that changes anything.

I would close that gap to .030-.035" and like AnOldUR said, try batch sparging. With 14.5 lbs. of grain you should have gotten 1.080-1.087 with 1.25 qts. per lb mash and 2 qts. per lb batch sparge. Yes it is a lot of water to boil off, but thats how to get higher efficiency.

My biggest increase in efficiency was realizing I wasn't stirring enough. I had bought a grain mill, tightened it up and was still getting around 70%, not much better than at my LHBS mill. Stirring really well at dough in, for 3-5 minutes before mashout, and then for 5 minutes after adding sparge and i'm consistently at 85% now.

Stir like crazy, then stir some more.

I usually stir during the initial add of the grains to the mash tun to break up the dough balls, and maybe once or twice throughout the mash process.

I'll try to adjust the mill for the next round of brewing on an IPA. I'll shoot for the low end around .030".

When I designed the manifold, I did it to avoid channeling and followed the general rules of thumb on them.

I went through all the stickies on here too just to make sure that I had everything covered before I posted. Thanks for the advice, I'll let you know how it turns out.

I can almost guarantee you that adjusting the mill gap to .035 will net you a solid 10-15 percent better efficiency since the rest of your process is pretty spot on!

Good to know! And thanks for the help! I don't mind throwing extra grain at it, but in the case of a Belgian Quad, I'm going to need the room for the standard grain bill and the mash /sparge water. Last one topped me out when it came out to 1.108. (With Candi Sugar)

Like everybody above said, it usually comes down to the crush. Depending upon which LHBS I go to, I know if I need to include an extra pound of grain in my recipe to account for hte poor crush. My friend and I call it the "brewmeister tax", since I need to buy extra grain at the lhbs named "brewmeister". lol