Very Low Efficiency for a Founder's Breakfast Stout Clone

I've been brewing for 3+ years now and I've never had an initial batch turn out so poorly. This is around the 25th or so all-grain batch that I've brewed. Target Gravity was supposed to be 1.08-1.09, 20lb of total grain but I only hit 1.065

Mashed at 155F for 75minutes (6.5 Gallons), and sparged with 3.5 Gallons @168F. This is for a 5.5 Gallon batch. Full recipe is posted below, does anyone have any idea what could have gone wrong?

Only thing I can think is that I recently started crushing my own grain with a cereal killer as opposed to crushing it at the store. But my last batch using this new crusher was an oatmeal stout seemed just fine as I hit 1.049 with BeerSmith estimating 1.052, same mill spacing...

Here's the exact recipe I used below:

14 lbs 8.3 oz Brewers Malt 2-Row (Briess) (1.8 SRM) Grain 1 76.1 %
1 lbs 8.2 oz Oats, Flaked (1.0 SRM) Grain 2 7.9 %
1 lbs 1.6 oz Chocolate Malt (Thomas Fawcett) (508.0 SRM) Grain 3 5.8 %
13.2 oz Roasted Barley (300.0 SRM) Grain 4 4.3 %
8.0 oz Black Barley (Stout) (500.0 SRM) Grain 5 2.6 %
7.7 oz Caramel Malt - 120L (Briess) (120.0 SRM) Grain 6 2.5 %
2.2 oz Carafa II (Weyermann) (415.0 SRM) Grain 7 0.7 %
1.00 oz Columbus (Tomahawk) [14.40 %] - Boil 60.0 min Hop 8 35.7 IBUs
1.00 oz Willamette [5.40 %] - Boil 30.0 min Hop 9 10.3 IBUs
2.75 oz Baking Chocolate (Boil 15.0 mins) Spice 10 -
1.65 oz Cacao Nibs (Boil 15.0 mins) Spice 11 -
0.50 oz Willamette [5.40 %] - Boil 2.0 min Hop 12 0.6 IBUs
2.20 oz Coffee Beans (Boil 0.0 mins) Spice 13 -
2.20 oz Coffee Beans (Secondary 0.0 mins) Spice 14 -

Est Original Gravity: 1.090 SG
Est Final Gravity: 1.026 SG
Estimated Alcohol by Vol: 8.5 %
Bitterness: 46.5 IBUs
Est Color: 56.5 SRM
Total Grain Weight: 19 lbs 1.2 oz

What are you using to measure SG?

What's your typical efficiency?

What's your gap?

Without going too in depth into Beersmith, I've got you at sub 50% efficiency, which I'm skeptical of.

I have both a set of 3 hydrometers and a refractometer to measure SG, which I know are fairly accurate. Typically I'm at 75-80% efficiency. I batch sparge in a 10 gallon cooler, the only thing that I can think of in this case is that maybe I sparged too quickly as I did leave the lever nearly all the way open for a relatively short sparge cycle. Either that or perhpas my local water profile has changed, though I don't know why that might happen...

That's a HUUUUGE drop. I'd almost lean towards the grain being measured improperly.

What were your pre-boil volume and pre-boil SG? Should be able to get some info about what happened from that.

You said you batch sparged, but left the valve open. Does that mean you didn't stir well after adding the sparge water?

Brew on

I'm new to brewing, but 10 gallons of water seems like a lot of water for a 5.5 gallon batch. I just brewed a Belgian stout with 16 pounds of grain. I used 8.5 gallons of water which was 0.5 to 0.75 too much. My target OG was 1.080 and I hit 1.066. Just a thought.

Not sure if it's related but I also just switched to a cereal killer mill and now get horrible efficiency compared to my lhbs crush. I'm typically off by 10 points or more. I've played with multiple gaps. Weird thing is plenty of people on here get great results with the cereal killer so ymmv.

gotbags-10 said:

Not sure if it's related but I also just switched to a cereal killer mill and now get horrible efficiency compared to my lhbs crush. I'm typically off by 10 points or more. I've played with multiple gaps. Weird thing is plenty of people on here get great results with the cereal killer so ymmv.

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What I've read is that you tighten the gap on your mill until it scares you, then tighten it some more. Efficiency is directly related to the quality of the milling with some other factors also like how much wort you might leave in the boiling pot by trying to limit the trub to the fermenter.

I had some similar issues with my monster mill 2, turns out the adjustment knob set screws had come loose and the gap had 'wandered'. I'd double check that the gap on the mill is set where you think it is, it definitely makes a big difference.
Do you typically make big beers like this? From what I've read and experienced, they tend toward less efficient mashes the larger the OG.

You know what, I don't think I actually stirred everything up when I sparged though I usually do, so that probably didn't help. I'll play around with the spacing on the cereal killer to see where it's at, it may have wandered off. I've done a few big beers, though I most tend towards stuff in the 1.05-1.06 range. I did brew a pumpkin saison a few months ago with 14.75lbs of grain, and I hit my TG of 1.075 with no issues which matched up with BeerSmith's estimate, though that was before I got the cereal killer.

I didn't check the pre-boil SG, though looking back I probably should have... volume was probably somewhere around 9 gallons from eyeballing it. I think for this beer I'm going to pick up some DME, boil it down to a syrup, and throw it back to the fermenter which is very happy with the 2L starter I provided it with.

UncleRusty said:

You know what, I don't think I actually stirred everything up when I sparged though I usually do, so that probably didn't help. I'll play around with the spacing on the cereal killer to see where it's at, it may have wandered off. I've done a few big beers, though I most tend towards stuff in the 1.05-1.06 range. I did brew a pumpkin saison a few months ago with 14.75lbs of grain, and I hit my TG of 1.075 with no issues which matched up with BeerSmith's estimate, though that was before I got the cereal killer.

I didn't check the pre-boil SG, though looking back I probably should have... volume was probably somewhere around 9 gallons from eyeballing it. I think for this beer I'm going to pick up some DME, boil it down to a syrup, and throw it back to the fermenter which is very happy with the 2L starter I provided it with.

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If you just quickly pour the sparge water thru the grain bed, rather than stirring it in well for about 5 minutes, all you did was a very inefficient fly sparge with lots of channeling. Channeling causes the sparge water not to contact, and therefore not rinse, the bulk of the grain bed. Very bad for efficiency.

It would also be almost impossible to get 9 gal pre-boil using only 10 gal of strike + sparge water. To do that with 19 lbs of grain, your grain absorption rate would need to be about 0.0526 gal/lb. BIAB'ers who squeeze aggressively can get down to that absorption rate, but for a traditional MLT absorption of about 0.12 gal/lb is more typical. That should put your pre-boil volume at about 7.7 gal.

Brew on

doug293cz said:

If you just quickly pour the sparge water thru the grain bed, rather than stirring it in well for about 5 minutes, all you did was a very inefficient fly sparge with lots of channeling. Channeling causes the sparge water not to contact, and therefore not rinse, the bulk of the grain bed. Very bad for efficiency.

It would also be almost impossible to get 9 gal pre-boil using only 10 gal of strike + sparge water. To do that with 19 lbs of grain, your grain absorption rate would need to be about 0.0526 gal/lb. BIAB'ers who squeeze aggressively can get down to that absorption rate, but for a traditional MLT absorption of about 0.12 gal/lb is more typical. That should put your pre-boil volume at about 7.7 gal.

Brew on

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Thanks, that makes perfect sense then. My boil kettle doesn't have indentations so I was just eyeballing it, but that does sound reasonable to me. Lesson learned!