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Terrible conversion

So just finished brewing a weizenbock. I’ve found my system to have around a 75% conversion. My last 3 recipes were DEAD on. My recipe entered into BeerSmith had me at 1.085. Pre-boil gravity was measured at 1.043. My crush was exactly the same and I used Brunwater to calculate my mash pH (5.3). This was the first time I have used wheat so i wasnt sure if I need to do something different when working with wheat.

Recipe was as follows:

9lbs dark wheat
4lbs Pilsner
1.5lbs Munich
0.5lbs C40
0.5lbs Special B
0.25lbs Pale Chocolate.

I only had 1lb of DME on hand but added it and had a post boil gravity of 1.063. Not terrible but nowhere near my target of 1.085.

Any suggestions on what I could have possible done wrong? That’s a HUGE difference in target vs. actual.

I’ve never used more than 50% wheat in my grain bills, but I’ve never had a problem with conversion, either. I did have a batch of Oktoberfest turn out about 16 points low a while back, but I contributed it to grain crush, as it was crushed pretty coarsely (before I started crushing my own grains). I see you said the crush was the same, so I don’t know. How long do you mash? I’m wondering also, how fresh are your grains? I just don’t see anything that jumps out at me from what you’re saying here…

I’ve read that wheat kernels are generally smaller than barley - and it certainly looks smaller to me - so the mill needs to be set to a smaller gap or the wheat needs to be run through twice. Wheat also seems tougher than barley malt. In other words I’d GUESS the problem is partly with the crush.

Boil longer to hit the target gravity.

Have you ever done a beer with that high of an OG? The larger grain bill the lower the efficiency.

I’ve done a 1.075 brew before and it was also spot on. Were talking almost .030 off. That’s not a small amount at all.

I added DME but would have boiled it for 3 hours to get it to my desired gravity. It’s really frustrating. I know I’ll still make beer. Just want to know what could cause this so I can prevent it in the future.

Yeah thats a lot I didn’t notice in you first post that you added the dme. I’ve used 50% wheat a few times with no problems. Wonder what happened?

I crush my wheat with the rest of the grain bill without changing the crush settings and have never had a problem. My OG is always pretty much spot on. Pretty strange to see that much of a difference. :?

I mashed at 152 for 60 minutes. Is it possible that a discrepancy in mash pH could make a difference of that much? It was the only thing I couldn’t measure.

Mash pH would have to be off by a LOT to cause noticeable differences in conversion efficiency, unless you only mashed for a short time, which you didn’t.

How do you do your sparge? The one thing that is significantly different when working with wheat is that it tends to clump into a dense mass, which can prevent the liquid from rinsing the grains effectively with some sparge techniques, or cause the sparge to get stuck. A lot of brewers add rice hulls to wheat-heavy grain bills for just this reason.

I’ve read that some brewers will adjust the gap on their mill to handle wheat better, or run it through twice to ensure a good crush. I’ve tried that, and never been able to notice a difference, but I crush pretty fine to begin with.

[quote=“rebuiltcellars”]Mash pH would have to be off by a LOT to cause noticeable differences in conversion efficiency, unless you only mashed for a short time, which you didn’t.

How do you do your sparge? The one thing that is significantly different when working with wheat is that it tends to clump into a dense mass, which can prevent the liquid from rinsing the grains effectively with some sparge techniques, or cause the sparge to get stuck. A lot of brewers add rice hulls to wheat-heavy grain bills for just this reason.

I’ve read that some brewers will adjust the gap on their mill to handle wheat better, or run it through twice to ensure a good crush. I’ve tried that, and never been able to notice a difference, but I crush pretty fine to begin with.[/quote]

I put a handful of rice hulls in there in anticipation of the wheat clumping. I didn’t have a stuck sparge but did have about 16 ounces of liquid sitting on top the clump. Not enough to account for the huge discrepancy. I ended up with a brewhouse efficiency of 55%. To me, the only way I can see having this big an error is forgetting to add 3-4lbs of base grain…which definitely didn’t happen.

Any chance your measurement equipment (or process) was off? A couple of times I pulled the wrong value off the Brix-SG chart when using the refractometer. The first time I was scratching my head for a good half hour before I checked the chart again … and realized what happened.

I used a hydrometer so chances aren’t too good that it’s off by that much. I haven’t ever checked it’s accuracy but its the same one I’ve always used. The only other equipment I could think of that would be off would be my scale but the only thing I measured out from bulk was the pilsner. Everything else came prepackaged in either 1lb bags or the wheat which I bought 10lbs of and actually weighed the remaining grain (after weighing the 9lbs out for the beer) just to see how close to 10 it was and it was almost spot on.

This is a real head-scratcher.

I wonder is conversion was slow due to the reduced diastatic power of the dark wheat?

Maybe, but an hour is pretty much overkill to get complete conversion unless your mash temperature is in the 140s, or your pH is way off, or some combination of such factors.

Your temp is right, diastatic power high enough, pH is reasonable, and it got plenty of time. Sounds to me like a dough ball.

I can’t pretend to be an expert chemist but I seem to remember from various readings that there is a very good reason why most wheat-centric grain bills do not exceed 50% wheat. How did you come by this recipe? If this brew works out and you like the way it taste, it would be interesting to do it again in the future with modified recipe to add more barley and reduce the wheat to 50% and see how it differs.

Hmm, this had not occurred to me and seems possible. My mash thickness was a little on the thin side (1.7qt/lb) so maybe a couple balls escaped me. Maybe it’s time to upgrade to a decent mash paddle :oops:

The recipe came from Brewing Classic Styles so it’s a tried and true recipe. The only change I made was to lower the grain bill to compensate for my “usual” higher efficiency since I believe that book assumes a 70% efficiency but ratios were still the same.

Hmm, this had not occurred to me and seems possible. My mash thickness was a little on the thin side (1.7qt/lb) so maybe a couple balls escaped me. Maybe it’s time to upgrade to a decent mash paddle :oops: [/quote]
Try a big stainless steel whisk. Cheaper and easier to get than a mash paddle, and works better on a homebrew scale.

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