Lower than expected efficiency when using wheat malts

[Morrey]

Last weekend was a BIAB Belgium Witbier with a projected post-boil (11G) OG of 1.049.

60% 2 row, 5% Flaked Oats, 35% Wheat Malts. Brew went perfectly...75 minute mash at 150F, full volume, ph 5.3, brewing salts adjusted. I ground the wheat separately (two mills) with a grind the same grist size as the grind I use for the barley malt grind. Did a mid-mash stir followed by a rinse/pour-over sparge after mashing for maximum sugar extraction.

My typical or average mash conversion efficiency when using only barley malts is right at 87%. When using wheat (despite grinding separately) my mash conversion efficiency always takes a hit, and this day I was at 77% mash conversion which is a full 10% lower than expected - resulting in missing target gravity. Instead of 1.049 as designed in BeerSmith, it was 1.044. Not the end of the world, but not what I am willing to accept as "good enough".

I know I can bump the amount of grains up slightly to accommodate the loss. I have enough data to know the "Kentucky Windage" method to put this % back on the money. HOWEVER, for the life of me I cant see what is causing these losses. Volumes exact, grinds precise, ph where I want it, temps right....just cant figure out why this is a pattern I cant dial in better than this.

 

[Yooper]

You could use a tighter crush on the wheat malt. They are huskless and smaller, and sometimes when I do it, they go right through my grainmill set at .032".

 

[cooper]

I'm going to be crushing up some wheat malt as well here in a few days, what's the sweet spot as far as gap set for running wheat only through?

 

[Morrey]

I'm going to be crushing up some wheat malt as well here in a few days, what's the sweet spot as far as gap set for running wheat only through?

I have 2 mills and both are 3 rollers. The gap between the bottom and top roller on my MM3 mill for crushing barley is .035. I don't have much experience with a 2 roller mill but my guess is the gap is different, but not sure if you have a 2 or 3 roller mill. On the Kegco 3 roller mill I use for wheat, I have it set at .030 so the grind I get with the wheat is the same as the grind I get from barley. Wheat is quite hard, the kernels are small with no husk, so the grind gap must be tighter than with barley.

I may try going a shade tighter with the wheat gap...maybe down to .028, but I'm getting lots of powder as is, so I am skeptical of going down in gap spacing much more. With that said, I have put a great deal of effort into getting a good wheat grind, so when I see efficiency issues as I did last batch, I almost throw my hands into the air with no real solution in mind.

 

[cooper]

No doubt! I have a barley crusher and it's currently set to .039 but I plan on closing that down to at least .035 and seeing what a cup of wheat looks like after I run it through and then adjust it if needed. I get a stuck sparge pretty easily in my 300 micron basket so I'm trying to find a sweet spot. Or else I'll hang up the $200 mesh basket and just go back to using a bag. Never had an issue using that.

 

[Morrey]

No doubt! I have a barley crusher and it's currently set to .039 but I plan on closing that down to at least .035 and seeing what a cup of wheat looks like after I run it through and then adjust it if needed. I get a stuck sparge pretty easily in my 300 micron basket so I'm trying to find a sweet spot. Or else I'll hang up the $200 mesh basket and just go back to using a bag. Never had an issue using that.

Don’t give up on the basket! Throw a handful of rice hulls in the mash!

 

[homebrewer_99]

I use the old Vitoria hand grinder (hooked up to a drill) and I just eyeball my wheat crush. Too large...no good...too powdery...no good.

One of the things I do (and recommend) when brewing with wheat is STIR the mash every 20 minutes.

 

[Smellyglove]

I usually grind the wheat at the same gap and speed as the barley, but for itself. It's finely ground. But, after going through several "WTH, again?" batches with extract potential data for each batch of wheat malt I was using from Castle Malting, I decided to turn down the extract potential from their "wheat-numbers" to regular base malt numbers and that was spot on.

 

[Morrey]

I usually grind the wheat at the same gap and speed as the barley, but for itself. It's finely ground. But, after going through several "WTH, again?" batches with extract potential data for each batch of wheat malt I was using from Castle Malting, I decided to turn down the extract potential from their "wheat-numbers" to regular base malt numbers and that was spot on.

I’ve been kicking that same idea around. If you were seeing the same issue I have been dealing with...something is off somewhere. I’ll adjust as you mentioned.

 

[Smellyglove]

I’ve been kicking that same idea around. If you were seeing the same issue I have been dealing with...something is off somewhere. I’ll adjust as you mentioned.

Yes, try that. I've got pretty good tracking of my preboil efficiencies (I do no sparge so I don't have the sparge-variable even) and this solved it for me.

 

[Morrey]

Yes, try that. I've got pretty good tracking of my preboil efficiencies (I do no sparge so I don't have the sparge-variable even) and this solved it for me.

Glad you mentioned this as I considered wheat malt issues before too. I have only bought and used Rahr white wheat malts, and my efficiency results have been very consistent, but low. Its not like my results have been all over the place...the low consistency issue is very predictable so maybe this tells me my process is nicely stable and the wheat malt's potential may be the culprit with miscalculations of the extract potential. Next brew, I plan to bump the wheat malt usage to compensate for the loss. Wheat is the only variable I can think of at this point.

 

[Smellyglove]

Glad you mentioned this as I considered wheat malt issues before too. I have only bought and used Rahr white wheat malts, and my low efficiency results have been very consistent, but low. Its not like my results have been all over the place...the low consistency issue is very predictable so maybe this tells me my process is nicely stable and the wheat malt's potential may be the culprit. Next brew, I plan to bump the wheat malt usage to compensate for the loss. Wheat is the only variable I can think of at this point.

If you're using a software try editing the wheat malt extract potential to the same as a base malt you've been using a lot, so you have some numbers to go after.

 

[Morrey]

If you're using a software try editing the wheat malt extract potential to the same as a base malt you've been using a lot, so you have some numbers to go after.

Ok, good tip. I use BeerSmith so I'll be changing the wheat extract potential to the same as the 2 row. Thanks!

 

[Smellyglove]

Ok, good tip. I use BeerSmith so I'll be changing the wheat extract potential to the same as the 2 row. Thanks!

I'm also using BS. I added the Castle Maltings pilsner malt numbers (which I obtained myself) into the wheat.

 

[chickypad]

Hey Morrey, if you're in the market for a new wheat malster you might try Great western white wheat. I've had good efficiency with that, using the 1.040 potential listed in Beersmith for it. Per the Morebeer site the kernels are bigger than your average wheat and less prone to crush issues as well - that could be true but I don't have any side by side measurements, I haven't used any other wheat malt in a long time.

 

[Morrey]

If you're using a software try editing the wheat malt extract potential to the same as a base malt you've been using a lot, so you have some numbers to go after.

I just edited the BS numbers for wheat down to 1.034 (from 1.040), and the newly projected efficiency in BS matched what I got on my last brew. So now I know what the real wheat potential is so I can go forward more accurately. I've still got 40 or so lbs of Rahr wheat left, so this number edit in BS will be good until I switch if something else is a better choice as @chickypad mentions below.

Hey Morrey, if you're in the market for a new wheat malster you might try Great western white wheat. I've had good efficiency with that, using the 1.040 potential listed in Beersmith for it. Per the Morebeer site the kernels are bigger than your average wheat and less prone to crush issues as well - that could be true but I don't have any side by side measurements, I haven't used any other wheat malt in a long time.

I have been buying 50# sacks from a local supplier and I was sticking with Rahr out of habit. Now that I may have learned this was not my best choice, I'll look into Great Western.

One of our local breweries allows me to purchase sacks of grains, so I let them know ahead of time and they just add-on to their order. I'll see if Great Western is an option on their purchase list. If not, I make orders from More Beer and always look for add-on items to make the $59 free shipping minimum.

Thanks for the suggestion!

 

[Smellyglove]

I just edited the BS numbers for wheat down to 1.034 (from 1.040), and the newly projected efficiency in BS matched what I got on my last brew. So now I know what the real wheat potential is so I can go forward more accurately. I've still got 40 or so lbs of Rahr wheat left, so this number edit in BS will be good until I switch if something else is a better choice as @chickypad mentions below.




I have been buying 50# sacks from a local supplier and I was sticking with Rahr out of habit. Now that I may have learned this was not my best choice, I'll look into Great Western.

One of our local breweries allows me to purchase sacks of grains, so I let them know ahead of time and they just add-on to their order. I'll see if Great Western is an option on their purchase list. If not, I make orders from More Beer and always look for add-on items to make the $59 free shipping minimum.

Thanks for the suggestion!

1.034 is pretty low, that's dark crystal malt-land. But you need to start somewhere, good call!

 

[Morrey]

1.034 is pretty low, that's dark crystal malt-land. But you need to start somewhere, good call!

Yeah, I realized 1.034 was getting on down there, BUT the numbers matched up perfectly. If this was a one time efficiency issue, I'd have questioned my process. Despite grinding separately, this low efficiency trend while using a large wheat bill has plagued me for some time now.

When making beers with no wheat, I am spot on the money...but add wheat in the grain bill, and I am off. But I am off consistently to the point I know what to expect. I could have arbitrarily tossed in another pound of wheat to compensate for the offset, but I really wanted to look into the efficiency issue with a bit more understanding. I appreciate your help and I like where this information is taking me.

 

[Smellyglove]

Yeah, I realized 1.034 was getting on down there, BUT the numbers matched up perfectly. If this was a one time efficiency issue, I'd have questioned my process. Despite grinding separately, this low efficiency trend while using a large wheat bill has plagued me for some time now.

When making beers with no wheat, I am spot on the money...but add wheat in the grain bill, and I am off. But I am off consistently to the point I know what to expect. I could have arbitrarily tossed in another pound of wheat to compensate for the offset, but I really wanted to look into the efficiency issue with a bit more understanding. I appreciate your help and I like where this information is taking me.

What you just said was exactly the same as I experienced. Seems like you're right on the money. If you're experiencing high/low efficiencies (seems like you have stuff under control and have good data) I'd tamper with that extract number instead of tampering with the amount of wheat.