Low Yield from Malted Wheat

[JimS]

I've been using Voyager Winter Wheat (Malted) to make neutral and have been getting repeatedly low yields (SG generally around 1.048). The SG calculators have been indicating I should be getting an SG of 1.07 (or better). I'm using a Grainfather G70 and have typically been using ~ 17kg of grain (so right at the upper end of what the G70 can handle). Been mashing in ~ 52L of water and sparging with ~ 20L to get about 52L in the fermenter. I've tried protien rests (30 mins at 50 degrees), I've tried adding enzimes, I've tried adding distillers malt (last batch was 9kg Wheat 8kg dilstillers malt). I have had a couple of slow sparges, so no doubt that has contributed on a couple of them, but I'm baffled while I continue to get such a low yield. Any thoughts/suggestions?

[renedox]

The SG calculators have been indicating I should be getting an SG of 1.07 (or better).

Is this from whereever you are getting your grain? It could just be that, that is what the grain you're using tops out at.

[howard]

i've been doing a couple of 5kg 100% unmalted wheat mashes with both HTL and gluco enzymes.
first time i only got 1.030, which was quite disappointing.

2nd mash i did a glucan rest and milled the 5kg of grain a lot finer, and got 1.055 (app quoted 1.052 for my grainbill and equipment)
the recirculation and sparging also improved on the 2nd mash.

i put your G70 and grain bill in my app and it reads 1.077 as you said.
i am going to use 7kg of unmalted wheat next time (my grain limit) to get me up to 1.072 (hopefully), to increase the abv of the wash.

[JimS]

Interesting, sounds like we are having the same problem. I wondered if I had a bad batch of grain as well. I tried a finer grind last time, plus a protein rest and still got a poor result. Hopefully someone knows what we are doing wrong, I’m certainly puzzled and will be avoiding wheat going forward unless I can’t work out what the solution is. Too much effort for the result at the moment I think.

[howard]

Interesting, sounds like we are having the same problem. I wondered if I had a bad batch of grain as well. I tried a finer grind last time, plus a protein rest and still got a poor result. Hopefully someone knows what we are doing wrong, I’m certainly puzzled and will be avoiding wheat going forward unless I can’t work out what the solution is. Too much effort for the result at the moment I think.

i don't think modern malted grains need a protein rest (from what i've read)
protein rest is different from a glucan rest.
i'm happy with my efficiency now.

[bluc]

Are you adjusting ph before adding grain?
Do you have couple thermometers and are you checking temp regularly?

[bluess57]

Not really much to add...
how long are you mashing for ?
iodine test that conversion is finished ?

[howard]

from reading today, there is certainly suggestions that a glucan rest is beneficial for malted wheat.
the glucan rest is probably a bit lower temp than the protein rest.
the Beta-glucanase enzymes probably won't survive 50C either, i think they prefer about 40C where they will dissolve the beta-glucans.
this might improve your viscosity, recirculating and sparging process later, for a better efficiency overall.
they make glue from wheat starch. :?
voyager winter wheat has a lintner of 64 according to my app, so the grains should convert easily.

[JimS]

Thanks for that. I ground my wheat quite fine (setting of 2 on the grainfather mill) and I used rice husks. I added the wheat and rice husks first and then the barley. Everything was mixed very thoroughly. I have read that one should add the coarser grain first (barley) and mix minimally (not go down to the bottom of the mash tun) so as to create a better grain bed filter. I'm wondering if by putting the wheat at the bottom and stirring the crap out of it I made a mistake? I recirculated the wort from the get go. It was fine for a while but my gut feel it was probably stuck (or very close to) the last half our or 45 minutes.

My Temp Profile was:
30 mins @ 50 degrees
90 mins at 65 degrees
15 mins at 75 degrees
Sparged at 75 degrees.
Boiled for 10 mins to sterilise.

I just used the grainfather temp measurement and didn't check with a thermometer. I didn't do a starch test but the liquid was relatively clear brown. I did note lots of "floaties" in it - which I haven't seen before. I was wondering if these were proteins clumping together? There was also quite a heavy scum on thee top during boiling which I haven't seen before.

Sounds like I should have done the initial rest at 40 degrees and not 50?

[howard]

Thanks for that. I ground my wheat quite fine (setting of 2 on the grainfather mill) and I used rice husks. I added the wheat and rice husks first and then the barley. Everything was mixed very thoroughly. I have read that one should add the coarser grain first (barley) and mix minimally (not go down to the bottom of the mash tun) so as to create a better grain bed filter. I'm wondering if by putting the wheat at the bottom and stirring the crap out of it I made a mistake? I recirculated the wort from the get go. It was fine for a while but my gut feel it was probably stuck (or very close to) the last half our or 45 minutes.

My Temp Profile was:
30 mins @ 50 degrees
90 mins at 65 degrees
15 mins at 75 degrees
Sparged at 75 degrees.
Boiled for 10 mins to sterilise.

I just used the grainfather temp measurement and didn't check with a thermometer. I didn't do a starch test but the liquid was relatively clear brown. I did note lots of "floaties" in it - which I haven't seen before. I was wondering if these were proteins clumping together? There was also quite a heavy scum on thee top during boiling which I haven't seen before.

Sounds like I should have done the initial rest at 40 degrees and not 50?

i'm not sure of your experience with brewing beer, but that sounds like a normal 'hot break' when you start to boil a wash.
i think it's just proteins and most folk just stir them back in.
i personally don't do the boiling step when distilling, some do.

there can be problems if the grain is milled too fine.
i just run it through my corona mill twice, i have no idea what that equates to in roller gaps. :smile:

i'm starting to dabble in high % grain rye whiskey & wheat vodka, the glucan rest is definitely needed for rye, and looks like wheat as well.
there is an enzyme to deal with beta-glucan, but i haven't resorted to it (yet)

do you use a recirculating arm during the mash?

[JimS]

Yes, I recirculate during the mash. As you say, maybe a 30 minute glucan rest at 40 degrees is what I need to do?

[bluc]

Def buy a couple(or one) instant read thermometer to double check temps dont rely on the built in one. My guess your not hitting temp targets..

[JimS]

Will do. Thanks.