Poor Efficiency BIAB Dunkleweizen

[FutureFarm]

I've made over 15 batches with BIAB. Always right around 75 +/- 2 % efficiency. Last night I made a dunkleweizen and got terrible efficiency. Using a brewhouse efficiency of 75%, I should have had an OG of 1.056. I ended up with 1.044. Grain bill follows.
50% Dark Wheat
30% Dark Munich
15% Caramunich II
5% Cara 120

I had a 122 degree protein rest for 20 mins. 149 sacc rest 30 min. 158 sacc rest 30 min. 170 mashout 10 min. Stirring as temperature increasing to prevent bag/mash scorch.

I do not alter my water, but I've never gotten this bad efficiency before. I've made wheat beers in the past and they've come out fine. Any ideas on why my efficiency was so bad?

 

[BargainFittings]

Did you crush your own malt?

 

[FutureFarm]

Nope. Crush at LHBS. Their mill is not adjustable by customers. I did not notice it being different from previous batches. Bought all my ingredients earlier on brew day.

 

[pricelessbrewing]

Without more information all we can do is guess.

Necessary info to 100% isolate the problem is gravity/volume/temp of

1) First runnings. This gives conversion efficiency.

2) Preboil/postboil info gives mash efficiency.

With both we can calculate the lauter efficiency and sparge efficiency, a new term I'm working on. Without first runnings there's not way to guess at the conversion efficiency, and so there's not way to know if it's extraction/conversion issues or sparge/lauter issues.

Anyways, to ask the typical questions...

Crush your own grains?

Fly sparge or batch sparge? Run off speed? Stir the sparge? How long did the sparge last?

 

[dstockwell]

I've made over 15 batches with BIAB. Always right around 75 +/- 2 % efficiency. Last night I made a dunkleweizen and got terrible efficiency. Using a brewhouse efficiency of 75%, I should have had an OG of 1.056. I ended up with 1.044. Grain bill follows.
50% Dark Wheat
30% Dark Munich
15% Caramunich II
5% Cara 120

I had a 122 degree protein rest for 20 mins. 149 sacc rest 30 min. 158 sacc rest 30 min. 170 mashout 10 min. Stirring as temperature increasing to prevent bag/mash scorch.

I do not alter my water, but I've never gotten this bad efficiency before. I've made wheat beers in the past and they've come out fine. Any ideas on why my efficiency was so bad?

Is this your first time using wheat. I BIAB and have had efficiency issues when using 40 - 50 percent wheat, has always been lower.

 

[FutureFarm]

This was a full volume BIAB. No dunk sparge. I tried to squeeze as much wort out of the bag as possible.

I have made wheat beers before that were 50% wheat and those were a little lower efficiency but still above 65%.

Thanks for the help/advice/concern.

 

[doug293cz]

To expand on @pricelessbrewing 's reply:

To fully diagnose efficiency issues, the following measurements are needed:

• Grain bill weight
• Strike water volume (everything prior to initial run off)
• SG of wort at end of mash, or first runnings SG
• Sparge process (fly, batch, none)
• Sparge water volume (for each batch sparge if more than one)
• Pre-boil volume
• Pre-boil SG
• Weight & type of any sugar added to the boil
• Post-boil volume
• Post-boil SG (OG)
• Volume into fermenter

Accurate measurements are critical, since the efficiency calculations cannot be better than the measurement accuracy. All volumes should be corrected for thermal expansion to 68˚F, or the volume measurement temperature reported, so that corrections can be made. Hydrometer measurements should be taken with the wort temp within 20˚F of the hydrometer's calibration temperature, and then corrected for the temperature at which the measurement was made.

Mash Efficiency = Conversion Efficiency * Lauter Efficiency
Brewhouse Efficiency = Mash Efficiency * Transfer Efficiency
Transfer Efficiency = Fermenter Volume / Post-boil Volume

With the measurements listed above, all of the factors in the above equations can be calculated. Conversion efficiency should be greater than 95%. Lauter efficiency is a function of sparge process and grain weight to pre-boil volume ratio, and maximum achievable can be predicted (but not as accurately for fly sparge.) Once you know which efficiency factor is lower than what should be achievable, then you know what part of your process needs to be addressed.

You said that you do no water adjustments. Which so much dark grain, this could have dropped your mash pH too low and affected conversion efficiency. But, without information on your water alkalinity and mineral content, this is only speculation.

Brew on

 

[laredo7mm]

Maybe part of it has to do with low diastatic power of your grains. Beersmith has dark wheat at 10 and dark munich at 25. IDK about the others, but they are probably very low as well since . Most roasted/toasted malts are.

 

[doug293cz]

Maybe part of it has to do with low diastatic power of your grains. Beersmith has dark wheat at 10 and dark munich at 25. IDK about the others, but they are probably very low as well since . Most roasted/toasted malts are.

If those DP numbers are anywhere near accurate, I think you may have found the problem. Good catch.

Brew on

 

[jjeffers09]

What was the L on your Dark Wheat

 

[SaucedBrews]

Is this your first time using wheat. I BIAB and have had efficiency issues when using 40 - 50 percent wheat, has always been lower.

Hah! Hahaha! I jumped here because my dunkelweizen came in around 56% efficiency. This thread was near the top. What a fortunate coincidence.

This is the first AG dunkel I've made and usually my main fermentable (porters, saisons, pales) is maris otter.

• 6 lbs Wheat Malt (Gambrinus) (2.3 SRM) (52.2 %)
• 4 lbs Munich Dark 30L (Gambrinus) (35.0 SRM) (34.8 %)
• 1 lbs Honey Malt (25.0 SRM) (8.7 %)
• 8.0 oz Crystal 170 Patagonia (170.0 SRM) (4.3 %)

I hit and held the mash temp (152) for a full 60. I didn't double-crush at the LHBS like I usually do but the crush looked good when I checked.

Thank goodness I overshot the ABV on this. It's now "in style" rather than being a strong dunkel. What do you do with your recipes to compensate for this efficiency drop?

 

[FutureFarm]

I bottled it today. Gravity was 1.012. ABV is out of style guidelines Tasted a sample and could really notice the cara 120. Had a noticeable toasty flavor. We'll see how it tastes cold and carbonated in 2 weeks.

 

[jjeffers09]

Weird guys I have the exact opposite in my system. I will get an 80-85% Brewhouse eff on wheat and rye and only 75-80% with a SMaSH brew. Malted wheat and unmalted wheat/rye have a higher extract potential vs two-row pils/pale malt. 1.0059 vs 1.0055 @75% efficiency per 1lb/454g per 5G/19L - Mosher Mastering homebrew pg 256. Malted wheat should convert without the help of base, but would be a bland beer. I would guess that you used too much dark munich. How did your pH turn out during the mash? How stable was the temperatures?

Wheat Farmers Daughter
80% efficiency
1.056 OG
1.014 FG 73%AA
16.24 IBU rager
0.28 BU:GU
18.2 SRM
64F Ferm Temp with 3638

Grist
58.02% German Red Wheat
20.01% German Light Munich
16.01% German Pils
3.00% Brown Sugar - dark
2.96% Briess Midnight Wheat

Tettnanger 4.7A .5oz - 60mins 11.03IBU
Mandarina Bavaria 6.8a .75oz - 10 mins 5.21

Step Mashed - double decoction

122F ~ 40 mins 1:1 dough in
@ 8mins 1/3 grist 150F for 10mins then boil for 18 mins
150F ~ 35 mins
@ 12mins 1/3 boiled for 18mins
168-170F for mash out 20 mins