Main reasons for low efficiency?

[arborman]

I've gotten a bit discouraged from my last two (and first two) all grain batches. My set up is a 10 gallon Rubbermaid cooler and a 10 gallon kettle.

I've done two kits, both from norther brew, and both pre crushed. I came in 60% or below on both. I have batched sparged, and held mash temps dead on at 152 for the full 60 minutes. All my calculations have come from beersmith. I'm a little reluctant to do another all grain and see low efficiency again. I think I'll do another extract while I figure things out

 

[Spinrathen]

The crush most likely is a reason for some of it undoubtedly. How are you batch sparging? Walk us through it so we can point out any possible bad techniques.

 

[crocks86]

My biggest problem from a few low efficiency batches turned out to be as simple as the way I stirred. I thought I was doing enough but then for a recent batch I took my time and added the grain very slowly and made sure there were no dough balls and it made a difference from previous batches (45-55%) to getting about 70% with the exact same crush.

 

[Jayhem]

In my experience it was the crush that played the biggest role!

I used to get 58% efficiency with the grain that my homebrew store milled for me. Once I got my own barley crusher I went to 75-80% efficiency with the same equipment!

 

[Tracebustin]

I've been having the same problem. I did the iodine conversion test last night, and all the starches had been converted. According to BeerSmith though, my efficiency was only about 53%. My guess is that it was due to the crush (crushed it at my LHBS).

Do you think it would be beneficial to me to run the grain through their crusher a second time?

 

[RM-MN]

To convert starch to sugars takes getting the grain wet at the right temperature. To get that done efficiently you need the grain particles to get wet through, not just on the outside. The smaller the particles the better they are to get wet through. If it was all flour, your efficiency would be nearly 100% and you'd get your mash stuck in the tun because you couldn't filter it to get the wort out. Stuck sparge? You bet. So with that in mind, crush is a balancing act between stuck sparge and poor efficiency. Do a better crush and your efficiency will go up. Get it crushed too fine and it will all stay in the mash tun.