New AG'er, Efficiency Problems

[OSB]

I'm new to homebrewing (last fall), new to all-grain brewing (last month), and new to this forum (today) and I've got some issues with my mash efficiency. Seems like this is a pretty common problem so I apologize for starting a new thread. I assure you that I read all the pinned threads and other articles that I could find before my most recent brew but I had problems again, so now I'm posting this.

Anyway, I've done two AG batches. The first one was done with grain crushed at LHBS and I achieved 62% mash efficiency. I wanted to improve but I wasn't really that upset. Seemed typical for how LHBS crush grains.

The batch I did yesterday was crushed by me using a corona-type mill and my mash efficiency was 54%! I set it to crush quite a bit finer than the LHBS. There were no uncrushed grains to speak of and plenty of smaller bits. Comparing it side by side to the LHBS crush, my base grain was way, way more ground up. Maybe I can go finer but I really don't think this is my primary issue - but maybe I am wrong.

Some more details on this recipe/results:

• 11.7 lb grain bill, going for 4 gallons into fermenter (using 62% as expected mash eff.)
• Used Beersmith to calculate 15.15 qt for strike water
• Nailed the mash temp exactly (151) and dropped no more than 1 degree during the 60 minute mash
• Vorlauf, drained tun, measured 1.073 after mixing up the wort that I drained
• 3.15 gallon sparge, was targeting the beersmith 168F temp for sparge water but it cooled too much, down to 165.
• Stirred it in and drained fairly quickly, end of sparge measured at 1.028
• Ended up with 5.25 gal at 1.043 preboil
• 10oz dextrose and boiled down to 3.1 gal at 1.073

I did some research last night and saw that I was not doing this sparge properly with respect to temperature. Beersmith wasn't clear, but I now know to correct that. I'm also not sure how much that is going to contribute to efficiency.

I used the efficiency calculator spreadsheet from Braukaiser to determine that I had just a 82.4% conversion efficiency (note: not mash efficiency) which seems to be the biggest problem and I just don't know why.

I included some pictures of the mash tun after I drained the sparge and poked around a bit. I don't know what dough balls look like, but I did have some clumps in there, not much bigger than a quarter or so. You can also see that my braid didnt stay flush to the bottom.

Any guidance would be greatly appreciated!

 

[wilserbrewer]

Sparge temp doesn't really matter, so that is not an issue.

My concerns are not stirring enough before and perhaps after the mash, crush. Can't really tell from the pics, but the grist appears coarse???

 

[wilserbrewer]

You could crush a 1/2 cup of grain and post dear ailed pics, but guessing you don't have any grain?

 

[madscientist451]

Your fist brew was 62% efficiency, the second was 82.4 %, doesn't look like a problem from here. When you drink beer, the numbers don't matter. What did it taste like? Are you happy with your beer?

 

[OSB]

Your fist brew was 62% efficiency, the second was 82.4 %, doesn't look like a problem from here. When you drink beer, the numbers don't matter. What did it taste like? Are you happy with your beer?

I should edit that to note that is the CONVERSION efficiency (according to the Braukaiser spreadsheet I've seen linked on the pinned threads about efficiency), not the mash efficiency.

Mash efficiency was 54%.

First batch tasted great, so no complaints. Just hoping to cut down on amount of grain used and be able to consistently determine how much volume I am going to end up with at the target gravity, since I had to boil off so much on the most recent batch.

 

[OSB]

You could crush a 1/2 cup of grain and post dear ailed pics, but guessing you don't have any grain?

Great idea. I actually bought a sack of 2-row for this batch so if I get the time this week, I will set up the mill and grab some grain from the bucket.

 

[McKnuckle]

As was mentioned, enthusiastic stirring both at mash-in and before sparging will help. Second, you lost a bit more volume than perhaps necessary - I calculated 6.9375 gallons used (15.15 qts + 3.15 gallons). You ended up with 5.25 gallons into the kettle. That's a loss of 1.6875 gallons. If you had NO mash tun loss it would equate to about 0.14 gal/lb of grain absorption. Typically I (and others) get more like 0.11, which would represent a loss of only 1.287 gallons for your 11.7 lb grain bill. Remember that mash efficiency takes volume collected into account, hence this would be relevant. Not saying it would gain you back many percentage points, but everything counts.

What was the actual grain bill with weight amounts?

 

[acidrain]

Why is your bazooka tube sticking out of the grain bed like that?

 

[OSB]

Thanks for the replies, guys.

The grain bill was:
10lb 11oz 2 row
0.5lb Dextrine
0.5lb Crystal 40

As for the braid poking up, I suppose that was due to it being moved around while doughing in or stirring the sparge. It doesn't fit straight backward but usually sits on the bottom just fine with a slight bend. I was planning on clamping on something stainless on the end to weigh it down in the future.

I just crushed a few grains tonight to show a representative of what I used. I'd say this sample has a few more uncrushed kernels than what I got when I did the brew. Aside from that, it looks like similar ratios of bits to husk shreds to flour.

As I mentioned before, I held my crushed grain next to the LHBS crush and it was definitely finer so I figured it would be OK. Looking at it some more, I am guessing I can tighten that knob a bit further. I set it by placing pieces of an old credit card in and tightening it down until it was somewhat snug but not super tight on them.

 

[wilserbrewer]

I see a fair amount of uncrushed grain, I would tighten the mill considerably more. The credit card gap is common on roller mills, not so much with a corona.

 

[OSB]

Ah, ok, that would make sense, regarding the credit card gap. Should I just tighten a quarter turn, check if I see any uncrushed grains, and repeat until there are none?

 

[McKnuckle]

Agreed, there's a lot more whole kernels visible than what I get with my roller mill, which has a fixed gap of 0.045". (Also I assume you know that the dextrine is unfermentable, meant to preserve body.)

 

[wilserbrewer]

Ah, ok, that would make sense, regarding the credit card gap. Should I just tighten a quarter turn, check if I see any uncrushed grains, and repeat until there are none?

I would work the other way, tighten till the plates are rubbing slightly, crush a cup and back it off if needed. The corona is far from a precision unit whereby you can measure the gap, pretty much trial and error till your satisfied with the crush. My advise would be to crank it down tight, and it looks like your a ways from there....NO UNCRUSHED. or very few

 

[stpug]

In addition to the crush, in your pictures you can see the remaining wort in the grainbed hanging out almost to the top of the grainbed. That's A LOT of undrained runnings, and when it's your initial runnings then that A LOT of high-sugar wort you're leaving behind to be diluted. While you will collect some of those sugars on your seconds runnings, you're not draining your grainbed well enough and therefore leaving behind large amounts of your converted sugars (and, in turn, efficiency percentage). I suspect from the undrained wort you're losing 5+% mash efficiency.

 

[swerner]

I think that screen sticking up was part of the problem also. I know you mentioned it above, but you really need to make sure that remains at the bottom of the mash. Good luck on your next brew.

 

[McKnuckle]

Just an unsolicited word in favor of the BIAB technique here, since we're talking about unrecovered post-mash wort.

With BIAB there is no wort lost in the mash tun, since the mash tun and the boil kettle are the same vessel. Also, while many BIAB practicioners squeeze their bag to recover absorbed wort, I do not, and yet I achieve a measured absorption rate of only 0.06 gallons/lb of grain (half that of traditional AG). How? By simply employing an extended gravity drain.

After the mash (and NO sparge), I hold up the bag and drain the gross volume of wort sitting in it, then I place it in a colander over a small pot. While the wort heats to a boil, which takes maybe 20-30 minutes, it drains into the pot. When the boil occurs, I dump this recovered wort into the boil kettle. But I return the bag to the pot yet again, to recover more! I have even left it there for the entire boil, and drained the contents into the wort at the end. It's not much at that point - maybe a cup at most - but it counts!

The grain is as dry as it's gonna get by that point. Since I also have done traditional cooler mashing where the grain sits in a container after the mash, I have seen the difference. The grain in the cooler is heavier with unrecovered liquid, simply because it remains piled up in a container with no way to drain out.

I do BIAB with one pass through my mill and no bag squeezing, and achieve about 85% ending kettle efficiency. Just a thought for the OP as he ponders his process.

 

[OSB]

Great tips, guys. I think I have a lot of new things to try on my next brew day.

In addition to the crush, in your pictures you can see the remaining wort in the grainbed hanging out almost to the top of the grainbed. That's A LOT of undrained runnings, and when it's your initial runnings then that A LOT of high-sugar wort you're leaving behind to be diluted. While you will collect some of those sugars on your seconds runnings, you're not draining your grainbed well enough and therefore leaving behind large amounts of your converted sugars (and, in turn, efficiency percentage). I suspect from the undrained wort you're losing 5+% mash efficiency.

Regarding this, I don't know what I can do differently. I basically drained the tun until it was trickling, then tilted it up to drain some more.

I also think the pictures may be deceiving. I dug out the grainbed a bit looking for some huge doughball or something first, then saw the wort sitting there in the bottom. It was probably only 1-1.5" deep, but I should probably try and get an accurate measurement of how much dead space I have in there.

 

[stpug]

Regarding this, I don't know what I can do differently. I basically drained the tun until it was trickling, then tilted it up to drain some more.

I also think the pictures may be deceiving. I dug out the grainbed a bit looking for some huge doughball or something first, then saw the wort sitting there in the bottom. It was probably only 1-1.5" deep, but I should probably try and get an accurate measurement of how much dead space I have in there.

Yeah, you may be right, perhaps the pictures are deceiving. Some of them made it look like you might have 2-3" of standing wort down there which in a 10gallon water cooler could equate to almost 2 gallons (minus solid matter of course), but still something significant.

 

[wilserbrewer]

JMO, the 1" of second runnings left in the tun is also being displaced by crushed grain, so you are really only forfeiting a small quantity of sugar left behind in a small quantity of low gravity second runnings wort. Not enough to impact efficiency, I would guess 1%. Now if you were doing full vol mash, perhaps a bit more. Tip the tun to drain it and move on, rdwhahb

When I enlarge the grain pics and the pics of grain in the tun, I see a lot of uncrushed....JMO

 

[RmikeVT]

You might want to try running your grain through the mill at your homebrew shop twice. Double crushing as some call it. I've never done it, as I have my own malt mill dialed in, but this might save you some headache and yield better efficiency. I did some simple math and figured out that buying my own sacks of grain and improving my effeciency paid for my barley crusher in 7 months of brewing.

 

[OSB]

JMO, the 1" of second runnings left in the tun is also being displaced by crushed grain, so you are really only forfeiting a small quantity of sugar left behind in a small quantity of low gravity second runnings wort. Not enough to impact efficiency, I would guess 1%. Now if you were doing full vol mash, perhaps a bit more. Tip the tun to drain it and move on, rdwhahb

When I enlarge the grain pics and the pics of grain in the tun, I see a lot of uncrushed....JMO

OK, did a brew with the LHBS crushed grain a couple weeks ago and again landed right around 60%.

Prepping for a batch this weekend, set up my mill last night and I got the following. Fine enough? Too fine?

 

[wilserbrewer]

Not too fine IMO. How does it compare to the LHBS crush?

Any uncrushed? I would crush a little finer....jmo

Old expression, "crush till your scared", then some crush a little more.

 

[stpug]

OK, did a brew with the LHBS crushed grain a couple weeks ago and again landed right around 60%.

Prepping for a batch this weekend, set up my mill last night and I got the following. Fine enough? Too fine?

That looks like a nice safe crush to me. Considering it a little blurry at full resolution, it looks like everything is cracked into several pieces without any full kernel left uncrushed. I would venture a guess that I would get between 70-75% fermenter efficiency (with minimal losses) using that crush.

It certainly looks good enough to brew with and then adjust next time if you want to.

 

[OSB]

Thanks for the replies. Got 64% mash efficiency yesterday.

I may crush finer next time, but we did have a little bit of a stuck sparge with our steel braid. At this point, I am starting to care a little bit less about the efficiency. As long as I'm consistent, I can live with having to toss in a couple extra lbs of grain.

Thanks again for the help.

 

[YeastMode]

Grain crush is only one factor with respect to efficiency. My brew system/process is basically the same as yours. Since you have received wise advise already regarding the crush, I'll skip over that part, except to say that crush is effected by both gap and speed.

To improve my efficiency, I stir the mash 2-3 times during the mashin process. When I mash in, I add some grain, add some water, stir well, then add more grain, more water, and so on. This makes sure that you limit (or eliminate) dough balls. Then I still it about every 15-20 minutes or so for maybe 10 seconds. I give it a few good, hard stirs and close it back up. Don't really have a meaningful temp loss, but I live in FL so it's 90 out anyway, and I try to keep my tun in the sun.

Setting the grain bed is important. I usually vorlauf 4-6 quarts at a minimum and usually more. When draining, I tip it forward before it starts to gurgle to try to keep a bit of siphon going. With all these efforts, I get fairly acceptable efficiency, hovering around 80%. I usually use an extra .5-1# of base grain, but sometimes I end up over by doing to.

Or, you can keep doing what you are doing and just up your grain bill to compensate. This will only be an issue if you move to very big beers, as the extra grain can push you to your capacity limits. But for your every day beers, you will have no problem.