Wheat malt and mash efficiency

I've recently noticed that my mash efficiency plummets when I use a decent amount of wheat malt in my mash. To see if this was really the culprit, I went through the past couple of years worth of recipes and plotted out the amount of wheat malt used (in lbs and % of grist) vs. my mash efficiency for the recipe. I know correlation doesn't necessarily equal causation, but I'm going to go with causation in this case. I am assuming that given the smaller kernal size the wheat malt is not getting crushed very well at my LHBS. I wonder if having the wheat crushed separately would work better.

Nice data and charts! I've seen the same thing. Im not sure what the cause is but I just factor it into my recipe formulation. I'll have to dig up my numbers this evening.

WoodlandBrew said:

Nice data and charts! I've seen the same thing. Im not sure what the cause is but I just factor it into my recipe formulation. I'll have to dig up my numbers this evening.

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My concern is whether the wheat is messing with the mash, thereby throwing off the whole efficiency or if I am getting normal extraction from the non-wheat malt and the lower efficiencies are just a result of poor extraction from the wheat malt. If it is the later, then in some cases I am only getting something like 20% efficiency for my wheat malt. Wouldn't this imply that my beers aren't quite as "wheaty" as I had planned them to be?

JLem said:

My concern is whether the wheat is messing with the mash, thereby throwing off the whole efficiency or if I am getting normal extraction from the non-wheat malt and the lower efficiencies are just a result of poor extraction from the wheat malt. If it is the later, then in some cases I am only getting something like 20% efficiency for my wheat malt. Wouldn't this imply that my beers aren't quite as "wheaty" as I had planned them to be?

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Most likely you are getting lower conversion efficiency from the wheat and your beers are not as "wheaty" as planned. The extract potential for wheat malt is generally the same compared to regular malts. You may have to mill your wheat finer or mash longer.

Kai

Jim, I'm going to echo what Kaiser said. For a small amount I don't think it makes a difference but for a brew with a big percentage of wheat it's probably worth the extra time and effort to mill the wheat separately. What I have done in such instances is first mill the wheat and then add that to the barley and mill all together. Like Kai said, the malted wheat itself should yield and convert with similar numbers to typical barley malt. The only other thing I'd add is that perhaps, just speculating here, the malted wheat is not as well modified as some of the modern barley malts. Because of that and because of its higher potential nitrogen content I always do some extended mashing time & temp with wheat.

I've read that what you have correlated (i.e. wheat malt not fully extracting due to crush) to be the case. I actually have my LHBS mill all barley malts together, and triple-mill all wheat and rye malts together. I definitely see the difference from the first to second milling (significant), and even more slight improvement in the third milling. At the end of the third milling, the wheat/rye malts begin to look like the single-milled barley. The few batches that I've brewed using decent percentages of triple-milled wheat/rye have produced expected efficiencies (72-74%), just like my all barley brews.

That's pretty much what I was thinking. I think this confirms it now. Guess next time I use wheat malt I'll ask to have it milled twice (If those slackers at my LHBS wouldn't mind. What do you think, BigEd?)

Guess this means my wheat wine is misnamed...which also explains the thinner body than I was expecting!

JLem said:

That's pretty much what I was thinking. I think this confirms it now. Guess next time I use wheat malt I'll ask to have it milled twice (If those slackers at my LHBS wouldn't mind. What do you think, BigEd?)

Guess this means my wheat wine is misnamed...which also explains the thinner body than I was expecting!

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I'll put in a word for you and get those lazy so and sos to get milling properly.

Just thinking out loud but I always thought most of the conversion enzyme existed at the husk/endosperm boundary. Since wheat doesn't have the husk intact are we not diluting available enzyme with higher percentages of wheat, leading to reduced conversion efficiency? Maybe finer grind overcomes this issue.

Looks what I have might be a laugtering and a conversion issue. The R-squared fits are terrible on my data, but it seem my efficiency drops 3% per pound of grain added to the mash tun, and drops about 0.4% for every percent increase in wheat in the grist.

very raw data here, sorry.
The chart on the left is Efficiency vs weight of grain in lbs (Total grain weight, not just wheat. This is a 4 gallon pot BIAB)
The chart on the right is Efficiency vs non-wheat percentage of the grist.

Since wheat has no husk, there's not much potential danger in grinding it to a coarse flour. If the LHBS mill has adjustable settings, you can mill it finer there. Otherwise, you might be better off keeping it seperate and seeing if you can use a food processor or something similar at home. If you do a lot of wheat beers, a $25 corona mill might be a good investment.

helibrewer said:

Just thinking out loud but I always thought most of the conversion enzyme existed at the husk/endosperm boundary. Since wheat doesn't have the husk intact are we not diluting available enzyme with higher percentages of wheat, leading to reduced conversion efficiency? Maybe finer grind overcomes this issue.

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According to kaiser, it's quite the opposite. Red and White wheat are on par with 6-row barley in terms of diastatic power.

Source: http://www.braukaiser.com/wiki/index.php?title=Understanding_Efficiency#Diastatic_Power