Sudden Drop in Efficiency

[Morrey]

On a regular basis I make a Hoppy Wheat beer based on 3 Floyds Gumball Head. I can pretty well count on 80% brew house eff and use 80% in BeerSmith for calculations. I may get a shade over 80% in most cases, but never less with BIAB.

I decided to try lemon grass (dried) in this recipe and ended up adding an ounce of it into the mash. When I mashed out and took a pre-boil SG reading, I was well below my normal reading. I boiled reaching my typical post boil vol and the OG reading was 10 points below my recipe's normal OG. Everything was identical including grind, chemistry, grain bill....identical. The only mod was the addition of dried lemon grass in the mash and my efficiency went from 80% down to 68%.

Was this radical drop in efficiency due to the addition of lemon grass in my mash?

 

[Gravity]

It shouldn't be, however, for control purposes and for best practices you should add adjuncts during flameout or during fermentation, not during the mash, unless you're doing oats etc.


I find it strange you added lemon grass during the mash .

This could also be Beersmith mistake as it may be doing something funky with the lemongrass addition at the mash

 

[Morrey]

I find it strange you added lemon grass during the mash .

I wasn't sure what to do with the lemongrass but originally considered flameout and dry hop additions.

I reached out to the head brewer at Sweetwater who brews with lemongrass and was told they add lemongrass into their mash...so I took that as a good idea. He didn't mention efficiency.

The base recipe I used remained unchanged and I have made hoppy wheat's with this recipe multiple times with predictable results. The only change I made was the lemon grass addition into the mash resulting in a huge drop in brew house efficiency.

 

[Lefou]

The only thing I could think of would be the lemongrass might've affected the mash pH.
I'd think an herb would be used more or less like a first wort hop, not a mash ingredient.

If Sweetwater's braumeister uses it in the mash, I'm wondering if he noticed an efficiency problem - or if he did, does it matter?

 

[Morrey]

I thought the same thing, Lefou, but I blindly followed his advice. His rationale was that using it in the mash eliminated the need to use and dispose of the lemon grass in a later addition needing to be contained like I would use muslin bags. He didn't mention efficiency, but as you said, maybe they don't sweat the details. I would, but that's just the way I roll.

I cant think of anything besides mash ph getting out of whack from the lemon grass. With all of my other recipe details remaining at such a proven level, I cant figure on anything else. Live and learn. The low OG caught me off guard to the point I completely glossed over adjusting back my 10 points with DME I use to build starters.

 

[Lefou]

If this happens, I'm going to hazard a guess and voice suspicions Sweetwater's braumeister might not treat his water, either. Wondering what other QA things might be second-hand priorities.
A lot of us hobbyists are more prickly over details. To me, 10 gravity points could be a whole other style.

 

[IslandLizard]

How much did you put in? If you have some of that lemongrass left, put a few pieces in some hot RO water, let steep and when cooled, take a pH reading. That may answer whether the mash pH was affected.

For some reason I doubt dried lemongrass is very acidic, it looks like wood chips.

How was the flavor, aroma? I never got much from the dried stuff in cooking, but I love it fresh!

 

[Morrey]

How much did you put in? If you have some of that lemongrass left, put a few pieces in some hot RO water, let steep and when cooled, take a pH reading. That may answer whether the mash pH was affected.

For some reason I doubt dried lemongrass is very acidic, it looks like wood chips.

How was the flavor aroma? I never got much from the dried stuff in cooking, but I love it fresh!

That's a great idea to test ph after I make a "tea" with the lemongrass. I bought a 2.5 oz bag at my LHBS and used 1/2 of it in my mash.

I used Sorachi Ace and Amarillo hops at FO and WP, so that eclipsed the aroma of the lemon grass at this point. I have 1.25 oz left over so I figured I'd see what influence the lemon grass had when I go to keg, then I could dry hop with the rest if called for.

 

[IslandLizard]

That's a great idea to test ph after I make a "tea" with the lemongrass. I bought a 2.5 oz bag at my LHBS and used 1/2 of it in my mash.

I used Sorachi Ace and Amarillo hops at FO and WP, so that eclipsed the aroma of the lemon grass at this point. I have 1.25 oz left over so I figured I'd see what influence the lemon grass had when I go to keg, then I could dry hop with the rest if called for.

Yep, those hops will cover up that lemongrass quickly. Boiling drives off the lemongrass fragrance too. No clue why that brewer put it in the mash.

What I forgot to say, your grist may have been courser than previous brews. That's the most common cause of lower efficiency.
Do you mill yourself? Maybe the gap has widened, slipping set screws.

 

[Sbe2]

What I forgot to say, your grist may have been courser than previous brews. That's the most common cause of lower efficiency.

+1. I got my grain from a different shop and I could see the difference in crush. Went from 75/76 down to 65.

 

[IslandLizard]

I just re-read the OP. It's a wheat beer! Wheat kernels are much smaller than barley, and should be milled on a narrower gap or they pass through mostly uncrushed. Look there first.

I've seen people leaving the LHBS proudly with their grist, with a load of whole kernels in the bag.

I crush Wheat, Rye, and Oat malt as well as flaked goods (for faster hydration/conversion) at 0.024"-0.026" gap. The thickness of an American Express junk mail credit card.

 

[daveMN]

Not sure how much an ounce contributes, but if it would add to the grain bill but not contribute any fementables, that would lower your efficiency on paper. I can't see an ounce of lemongrass dropping pH that much, given malt's buffering capacity. Same strike and sparge volume as normal?

 

[Gravity]

The only thing I could think of would be the lemongrass might've affected the mash pH.
I'd think an herb would be used more or less like a first wort hop, not a mash ingredient.

If Sweetwater's braumeister uses it in the mash, I'm wondering if he noticed an efficiency problem - or if he did, does it matter?

A drop in efficiency isn't the end of the world , however I totally agree, its not a mash ingredient.

One should dry hop with it after soaking it in Vodka or the like. I would imagine larger brewers care less about efficiency seeing as they have more of everything to spare.

 

[Morrey]

Yep, those hops will cover up that lemongrass quickly. Boiling drives off the lemongrass fragrance too. No clue why that brewer put it in the mash.

What I forgot to say, your grist may have been courser than previous brews. That's the most common cause of lower efficiency.
Do you mill yourself? Maybe the gap has widened, slipping set screws.

I use an MM3 mill and keep the gap the same although I do check it every few brews. I always dip my hand into the milled grain and scoop up some to take a look at the grist size. Appeared normal as usual but I'll check the gap with feeler gauges before my next brew day.

I think I'll not only check the lemon grass tea's ph as you suggested, but you have given me an idea to take it a step farther. I propose to do a test mash with the same proportion of adjusted water to grain that would be my normal mash ratio. Two batches...one with lemon grass, other w/o and see what the refractometer says as well as the ph meter.

Something went wrong here, but one thing I'll say w/o hesitation...if I am pleased with the lemon grass results, I will only use it in the whirlpool phase and/or the dry hop phase next time around.

 

[Morrey]

I just re-read the OP. It's a wheat beer! Wheat kernels are much smaller than barley, and should be milled on a narrower gap or they pass through mostly uncrushed. Look there first.

I've seen people leaving the LHBS proudly with their grist, with a load of whole kernels in the bag.

I crush Wheat, Rye, and Oat malt as well as flaked goods (for faster hydration/conversion) at 0.024"-0.026" gap. The thickness of an American Express junk mail credit card.

I totally see your point. One factor to consider is that I have done multiple batches with this exact recipe (same grind) so I have a pretty good reference point of the OG this same recipe will give me on a consistent basis. The lemon grass was the only thing I changed in this recipe that I have done multiple times.

Going forward, this is darn good info to use when I mill. This particular recipe had 5 lb 2 row, 4 lb white wheat and .5 lb aromatic. Drawback is the MM3 is a PITA to take the cover off and check the gap or adjust the gap. I wish this was easier like a 2 roller mill, but the gap I set is between the bottom roller which you cant see from above and the top drive roller.

Given my normal efficiency is 80% BH, if I tighten the gap for the wheat grind, then back to normal for 2 row, would you predict a bump in efficiency?

 

[Morrey]

A drop in efficiency isn't the end of the world , however I totally agree, its not a mash ingredient.

One should dry hop with it after soaking it in Vodka or the like. I would imagine larger brewers care less about efficiency seeing as they have more of everything to spare.

When he emailed me with the proposed use of the lemon grass, I think he would have mentioned efficiency losses had he been aware. It would have been very easy to add a bit more grain into the mash to compensate. I wonder how tight a large brewery really tries to maintain efficiency?

Granted 10 points in efficiency loss wont cause me to dump the beer...so what...isn't the end of the world. Of course its good to know what causes issues when we see them since it only increases our awareness of the process. This is a good learning experience for me.

 

[Gravity]

When he emailed me with the proposed use of the lemon grass, I think he would have mentioned efficiency losses had he been aware. It would have been very easy to add a bit more grain into the mash to compensate. I wonder how tight a large brewery really tries to maintain efficiency?

Granted 10 points in efficiency loss wont cause me to dump the beer...so what...isn't the end of the world. Of course its good to know what causes issues when we see them since it only increases our awareness of the process. This is a good learning experience for me.

I'll drink to that

 

[IslandLizard]

I totally see your point. One factor to consider is that I have done multiple batches with this exact recipe (same grind) so I have a pretty good reference point of the OG this same recipe will give me on a consistent basis. The lemon grass was the only thing I changed in this recipe that I have done multiple times.

Going forward, this is darn good info to use when I mill. This particular recipe had 5 lb 2 row, 4 lb white wheat and .5 lb aromatic. Drawback is the MM3 is a PITA to take the cover off and check the gap or adjust the gap. I wish this was easier like a 2 roller mill, but the gap I set is between the bottom roller which you cant see from above and the top drive roller.

Given my normal efficiency is 80% BH, if I tighten the gap for the wheat grind, then back to normal for 2 row, would you predict a bump in efficiency?

Yeah, I guess 3-roller mills are more of a pain to adjust. But you can get to the 2nd gap from underneath, isn't it? I don't think for 3-roller mills adjustments for kernel size is as important because of the inherently better design. Sighs... I may want a 3-roller mill when I come across one. I did actually, a few months after I bought the 2-roller. It was built into a nice looking, small rolling cabinet too for only $100 more...

A small but important detail. At least this is the case on 2 roller mills, the direction the eccenters move when making gap adjustments should be from underneath, toward the gap, then lock them down. That way the eccenters push against the lock bolts when under force. If they were locked down in the move-away direction, the gap could widen during milling. I'm quite sure MM has exact directions for your mill. I noticed it made a significant difference while the gap stays put.

Since you check your milled grist, which is excellent practice, you would have seen a fair amount of whole wheat kernels if they went through uncrushed, and you'd knew something was wrong. 3-roller mills tend to crush somewhat better (less husk damage) than 2-rollers (more of a crude, forceful approach). For wheat and such the entrance angle to the 2nd gap may be all that's needed to get them crushed right.

That said, I would definitely check that gap, perhaps tighten a smidgen and see if things improve. Even .002 tighter can make a noticeable difference in mash conversion and efficiency at that level. That's why I mill "flaked" goods (rolled would be a more accurate description, especially for oats), they're only partially pre-gelatinized [Palmer].

If you have a non-recirculating mash system and batch sparge, grist can be a whole lot finer than when recirculating or fly sparging. With BIAB the 0.000" gap appears to be the limit.

 

[Morrey]

Yeah, I guess 3-roller mills are more of a pain to adjust. But you can get to the 2nd gap from underneath, isn't it? I don't think for 3-roller mills adjustments for kernel size is as important because of the inherently better design. Sighs... I may want a 3-roller mill when I come across one. I did actually, a few months after I bought the 2-roller. It was built into a nice looking, small rolling cabinet too for only $100 more...

A small but important detail. At least this is the case on 2 roller mills, the direction the eccenters move when making gap adjustments should be from underneath, toward the gap, then lock them down. That way the eccenters push against the lock bolts when under force. If they were locked down in the move-away direction, the gap could widen during milling. I'm quite sure MM has exact directions for your mill. I noticed it made a significant difference while the gap stays put.

Since you check your milled grist, which is excellent practice, you would have seen a fair amount of whole wheat kernels if they went through uncrushed, and you'd knew something was wrong. 3-roller mills tend to crush somewhat better (less husk damage) than 2-rollers (more of a crude, forceful approach). For wheat and such the entrance angle to the 2nd gap may be all that's needed to get them crushed right.

That said, I would definitely check that gap, perhaps tighten a smidgen and see if things improve. Even .002 tighter can make a noticeable difference in mash conversion and efficiency at that level. That's why I mill "flaked" goods (rolled would be a more accurate description, especially for oats), they're only partially pre-gelatinized [Palmer].

If you have a non-recirculating mash system and batch sparge, grist can be a whole lot finer than when recirculating or fly sparging. With BIAB the 0.000" gap appears to be the limit.

You hit on something that lots of folks with mills make mistakes dialing in the eccentric rollers. When I bought the MM3 I watched his videos how to do this adjustment by adjusting (tighter) CW on the drive side and CCW on the non-drive side. Some folks get this screwed up meaning that you can have a tiny gap on one end and a wide gap on the other resulting in a big variation on the crush.

Yeah man, I am proud of the crush I am getting now. At first I ran the mill with a 1/2 inch 10 amp corded DeWalt drill that had tons of power. The kind of power that can sprain your wrist if you don't have a tight grip. Since milling is one of the things about home brewing that is an enjoyment to me, I built a grain mill stand and set it up with a motor that can go forward of course, or go backward if I happen to get into a roller bind. But I don't see this happening as I think this bad boy will crush pea gravel with the amount of torque it has. I can put 1 full hopper in place, flip the on switch and it never flinches. Gotta show it off here....