Wheat Malt Conversion Problem? Efficiency Plummets

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

KidDynamite

Active Member
Joined
Nov 27, 2011
Messages
31
Reaction score
0
Location
Hopkinton
Hey folks - here's the situation:

I brewed my 16th batch of homebrew today (I've been brewing for less than a year). Most of my batches have been small (1 or 2 gallon) all grain batches. I've found that my efficiency is generally about 69% in my mash.

Today I went to brew a base for a fruit beer (not sure if it's gonna be blueberry or raspberry yet - depends what looks good at the store next week), using a recipe that I found somewhere online (perhaps here?). The fermentables for a 2 gallon batch were:

2 lbs pilsner malt
2 lbs light wheat malt.

my LHBS had Weyermann's for both, and he milled them for me as usual. I stuck to my usual procedure: mashed for an hour at about 154-158 degrees, stirring after 30 minutes. Then I pour from my mash tun (a cooler) into a paint-strainer bag in my kettle. I sparged with about 2 1/2 gallons of 170 degree water. Now, I sparged a little more lax this time: I didn't take my paint-strainer-bag full of spent grain out and recirculate the sparge water over it - I just swished it around for a few minutes.

Anyway, fast forward: I did my boil, cooled my wort, and checked my OG: it came to about 1.029 - WAY below the 1.053 I was expecting from Hopville's stats:

http://hopville.com/recipe/1558371/home-brew/fruit-base

now, one problem is that I actually had a bit too much wort - 2 1/2 gallons - so it was too diluted. But even if I change the batch size to 2 1/2 gallons on Hopville, this equates to less than 50% efficiency. WTF?

Is there something odd with the convertability of wheat malt? I read somewhere that people said it needed to be milled finer perhaps? With a 50/50 ratio (pilsner/wheat) it should work in theory, right?

So was the terrible efficiency result just a consequence of me being a sparge-tard? Or do you think something went wrong with my conversion?

I partially remedied the issue by adding a bottle of home made maple syrup (dissolved in water), to get my OG up to 1.040... That was ok with me, as I figured a lower ABV would be ok anyway, plus I may get a small sugar bump from the fruit which I'll add after primary...
 
Hey KD

You said you sparged with 2.5 gal of water. How much water did you use for the mash? I figure if you used a normal mash of 1.25 qt water/lb grain that would be 1.25 gal of strike water. Then you have about .4 gal lost to grain absorption. That would give you about 3.35-3.5 gal of wort and that would yield a predicted OG of 1.03-1.032, which would be in the neighborhood of what you got.

Did you really end up with just 2.5 gal of wort?

I have no idea what could have caused this big a miss if the final vol you gave is correct.
 
Onlooker - I used 1 1/2 gallons of water for the mash. Slightly thin, perhaps. Would that negatively affect my conversion?

The 2.5 gallons was post boil - not sure if that was clear... And the 2.5 gallons is pretty accurate, I think. I didn't measure it exactly, but i am using a 3 gallon glass carboy, and it was past my 2 gallon line, but not quite to the top...
 
Oh, OK, I see now. Oops, I was mixing up my pre-boil OG figure with the post-boil vol.

Your thinnish mash isn't likely any problem. And I'm sure that you didn't have any clumps/dough balls, right?

The only thing I can think of is that your temperature was significantly higher than you thought is was and thus your conversion suffered. Any chance your thermometer isn't calibrated? Just a thought.

You're right that wheat should normally be milled finer. So maybe that is the problem. The only difference in mashing wheat that I've been able to find is to add a protein rest at about 122* for a while, but that's just for head retention, as far as I know.

That's all I've got. Good luck
 
Wheat does have a low diastatic conversion power compared to other malts. Many people strectch their mash out to 90 minutes when using wheat or would use 6-row instead of pilsner. Your mash temps seem fine, but a little on the high side for what I like unless your thermometer is off and you were mashing significantly higher than you thought.
 
I would blame it on the crush. wheat always brought down my efficiency when I had it crushed at lhbs, 40% I got on one batch. I now crush it at home as fine as I can get it and my efficency went up tremendously. May be longer mash and ph and whatever else may affect it but I would assume it wasn't properly milled at the store first.
 
thanks for the replies.

Onlooker - no dough balls - the mash looked good.

others: I have not calibrated my thermometer, but it's the same one and the same method I've been using for all my previous batches and I never had a problem - even the one time I accidentally mashed at 180 degrees because I was mashing in a pot on the stove instead of in my cooler.
 
Must be the crushing of the wheat then, it seems. Maybe talk to the LBHS about how they crush wheat and tell them your experience. At least to help prevent future problems, for you and others.
 
I have a similar problem with my wheat beers. I am pretty sure it is crush, but I haven't researched pH.
 
I like a long mash time and a protein rest for wheat. While technically the protein rest is for head retention - it also give you more time to hydrate the grain. I do lose efficiency on wheat recipes - but not too much, 5-10% at the very worst. I do extend mash times to 90 minutes when working with wheat. that plus a protein rest and I'm looking at nearly 2 hours of total wet grain time to end of sparge.
 
I'm really glad I read this thread. I'll be doing a wheat beer this weekend that will be my first in a about three years and first AG wheat ever. I was just going to crush same as every other grain, but I will be sure to set the gap a little tighter for the wheat. Does anyone have any suggestions as to what gap I should use for the wheat? Sorry to hijack the thread, but I figure it would be good info for the OP, too.
 
One of my club members uses flour instead of wheat Walt at has excellent results might want to ponder that route.
 
I would blame it on the crush. wheat always brought down my efficiency when I had it crushed at lhbs, 40% I got on one batch. I now crush it at home as fine as I can get it and my efficency went up tremendously. May be longer mash and ph and whatever else may affect it but I would assume it wasn't properly milled at the store first.

Must be the crushing of the wheat then, it seems. Maybe talk to the LBHS about how they crush wheat and tell them your experience. At least to help prevent future problems, for you and others.

I have a similar problem with my wheat beers. I am pretty sure it is crush, but I haven't researched pH.

+1 on the crush...I double milled the wheat on my recent Hefe (you can mill your own grains at the LHBS...), and my efficiency was right up with my usual...last beer I made with any significant quantity of wheat was 10% under.
 
thanks a lot for all of the crush info, folks.

I talked to my LHBS yesterday, and asked him if he could run the wheat malt through the crusher twice next time. He said that they've tried that but it doesn't really work with their grinder (note: this LHBS is awesome - incredibly helpful and willing to measure out tiny quantities of grains and hops for even 1 gallon batches)

my LHBS does have 1 lb bags of dry wheat malt extract, so maybe i'll just go with that next time (blasphemy!)
 
my LHBS does have 1 lb bags of dry wheat malt extract, so maybe i'll just go with that next time (blasphemy!)

not blasphemy. my last "broken" hefeweizen was way low on gravity and I fixed it after the fact by boiling up some DME and adding it to the fermentor. Wife said it was the best hefe she had tasted.
 
Wheat does have a low diastatic conversion power compared to other malts. Many people strectch their mash out to 90 minutes when using wheat or would use 6-row instead of pilsner. Your mash temps seem fine, but a little on the high side for what I like unless your thermometer is off and you were mashing significantly higher than you thought.

Wheat malt has about the highest diastatic power known to man.
 
Back
Top