Low Efficiency....like really low

I was brewing up a dark cascadian ale today. Measured my SG and it was much lower than what I was going for. My water amount was spot on. Pre boil and post boil collection was good.

My targeted OG was suppose to be 1.075 and I measured 1.056. Way low!

I calculated that it was roughly 55% efficiency.

I guess I just don’t know how I would be so low. I batch sparge. Rather frustrated but I will just roll with it.

Any suggestions? Only thing I can think of is bad crush at the LHBS.

That would be my first guess.

Thats what I thought too.  Never heard any fellow club members complain about the crush from the LHBS…but who knows.  might just have to see about getting a mill.  I just can’t believe that I was that far off.

If there’s nothing else obvious my first thought is that the reading was bad. Hydrometer/refractometer calibration checked recently? Sample temp was right? Did you try pulling a second sample just to double check?

Calibrated the hydrometer…and was spot on.  Left the sample at room temp roughly 60ish.  and it it rose to roughly 1.058…but still rather low.  I wish I could figure it out.  I guess next time just have to really take some good notes.

Thanks all of the suggestions and feedback.

All good advice.  Also, did you hit your volumes pretty accurately ?  If your post boil volume was higher than intended, you would end up with a lower gravity.

Hit my volumes rather spot on.  no idea what else it could be.

I’d say crush too. Also did you stir the mash? Did you stir like hell for vorleuf? Makes a difference as well as when you sparge.

FWIW I mash in a pot with a bazooka screen and I batch sparge.After the second running is drained I use a smaller lid from a different pot inside my mash tun to press the grains. I can usually get an additional 1/2 gallon of extra wort per 10# of grain. Boosts the OG 2 or 3 points quick and easy.

One more idea - is your mash thermometer calibrated? If you missed your mash temp by enough that could be an explanation.

All really great suggestions. Thanks everyone. I will try more stirring, pressing if off on volume and calibrating my thermometer.  I’m brewing in 2 weeks so I will report back. Just need to get a mill or hit up one of my friends.

FWIW, when I started AG brewing I worked on all the variables individually to get my process as efficient and consistent as possible ( calibration, volumes, measurements, pH ,etc.) and could not get above ~ 68% efficiency at best. It was frustrating because I knew my process was sound. The only thing left was my crush.  So I had my LHBS double crush my next batch and my efficiency went to right ~ 80% with otherwise the same process.  I’ve gotten my grain double crushed ever since.

+1 - My efficiencies were all over the place when I first went AG until I got my own mill. That was largely because I’d get my grain from all over the place - multiple online shops and a couple of LHBS’s. The crush was different everywhere and my efficiencies ranged from the upper 60’s to the mid 80’s. Once I started milling my own grain my efficiency was rock solid in the low 80’s from then on.

Do you brew a lot of dark beers? What was the mash pH?

Looks like a mill might be the next investment…and probably a smart investment.  I asked about having the LHBS double crush and they were hesitant to do so because they indicated it clogs/gets stuck in their mill, so I didn’t push the idea.  I usually run it through their electric/belt driven mill, but they do have manual mills.  I will see if I can adjust that mill and use that.  Just carve some milling time out of my weekly visits.

I don’t make a lot of dark beers and didn’t measure the ph.  I need to include that in my process but just haven’t made that move yet.

Thanks again.

If you started with a rather low pH to begin with, the addition of dark malts would push the pH out of the lower end of the range.

Just had the water conversation with a group of homebrewers at our study group last night.  Really need to start working with the water.  Our water is rather low in everything. Need to pick up some salts for the next brew

Well…I think I figured it out!  It was my crush.  I just brewed a belgian dubbel with a 13.95# grain bill.  Decided to hand crush the grains using the mill at the LHBS.  The crush was noticeably finer and what I would expect a good crush to look like.  While it ended up being the longest brew day yet…I hit 76% efficiency.  Really happy with it and just a smidgen over my anticipated OG.

While the efficiency was much better than I had hoped for, I did end up with a rather slow run-off on both mash out and sparging.  I think I may just go a little bigger on the gap next time.

Thanks everyone for their suggestions.  Now if I could just seem to get my temps and water volumes spot on and not drop my ph strip in the mash, I would be very excited…but I am still tweaking my system.

Thanks again and brew on!

You could also just throw a few handfuls of rice hulls in the mash to help with the run off!

That’s the nice thing about having your own mill. Get a decent set of feeler gages and keep track of where it is set. I use a sharpie and mark the side of the mill what the gap is set for. I also use an overnight mash (start about 11pm in a square ‘cube’ blue cooler, and start draining it about 6-7am).  I can’t remember when I didn’t hit my numbers.