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Old 03-20-2013, 06:09 PM   #71
ryangibson77
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My first thought regarding your low yield issue is that your grain may not have been crushed. Do you crush your own grain, or buy it crushed? Also, it is possible your strike water denatured a bunch of the enzymes if your strike water was too hot.

Regarding the yeast issue, do you know how old it was? Did you oxygenate? It's possible that if the grain wasn't crushed, a side effect of the low yield may be a lack of nutrients in the wort that the yeast count on for propagation. Someone else with a greater knowledge of yeast metabolism would have to chime in on this one though.

As far as saving the batch, I would buy some yeast energizer from your local HBS and see if that helps. Have you tasted it yet? As long as it tastes decent, I'd just plan on drinking it fast, since it'll basically be a "session" beer, and then just try it again.

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Old 03-20-2013, 06:16 PM   #72
SKooT1027
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Thanks for the quick reply.

I had the grain crushed at my LHBS about one month prior to use. I'm wondering if maybe it wasn't crushed enough. Strike water was 160, expecting it'd drop to 154. It only went to around 157, so I left it uncovered and stirred for around 10 minutes until temp dropped to 154. Then I covered and left it. Overall, I thought this brew process went better than my first two, so I was surprised by the low OG.

I didn't do anything to the yeast other than 'smack' the activator, give it a few hours to puff up and pour it in. Yeast was around 6 weeks old. I figured the loss to age would be offset by using the full pack in a 2.5g batch.

Beer tasted pretty decent. It'll obviously be very low abv (2.5%?). I didn't want to risk bottle bombs by carbing at that high of a FG, so that's why I decided to try more yeast.

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Old 03-20-2013, 07:14 PM   #73
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Based on what you've said, I'd bet the crush was poor...either the grain mill wasn't adjusted correctly, or there was uncrushed grain mixed in with the crushed grain or something... even at 160° strike temp, you should still have quite a bit of Alpha Amylase, so your wort may have a high FG, but the OG should still be where you'd expect it...oh, how long did you mash for, and did you do an iodine test to see if all of the starch was converted? I suppose if you did a 20-30 minute mash you might see that too...I mash a minimum of 45 minutes, plus a 15 minute vorlauf before sparging. I've never done a BIAB though...how about mash thickness? I think thicker mashes can tend to be less efficient... I typically do 1.1:1 water to grain or higher. Makes it easier to stir and gives the enzymes plenty of room to work. Anyway, just throwing out some ideas.

About the yeast...if the smack pack swelled up prior to pitching, I'd say the yeast were viable...but if the wort were under oxygenated, and/or lacking in DAP, the yeast would have a hard time propagating to sufficient quantities to start the fermentation stage and just got stuck. Adding some DAP and re-oxygenating may have done the trick. Also if the yeast you used is highly flocculent, you'd probably need to stir up the yeast cake after a stuck ferment. Sometimes the yeast just settle out if they never get started and pack so tightly that even after a DAP and O2 infusion, they just stay dormant.

Anyway, I think what I'd do is bottle in plastic soda bottles. They are much more forgiving, and you can "feel" the pressure in them, so you don't have to worry about bottle bombs.

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Old 03-20-2013, 07:36 PM   #74
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Thanks for the input. I mashed for 60 minutes, then just pulled the bag and squeezed the grains, extracting about 1-2 cups of liquid from it. There's no sparge in BIAB. Same with mash thickness, to get a final volume of 2.5g I estimated somewhere around 4.25g initially with the grains, which ultimately boils down to the final volume - although I overshot and ended up with more like 2.75g at the end.

I'm thinking it may have been an issue with the grains. I got my other grains from the same shop in the past, but maybe in the future I'll ask them to run it through twice.

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Old 03-20-2013, 10:03 PM   #75
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Without sparging, I would expect a fairly low efficiency, like maybe 50%...but if you've brewed using BIAB before and got significantly higher efficiency, then it would seem to point to the grain crush being the issue. I average about 72% efficiency in my all-grain system, which is fairly low, but it hasn't been a real priority for me to improve it until recently.

My next batch I plan on running the grain through my mill a second time to see if it makes a difference. Then I may try adjusting the roller gap. Also, I think I'm doing a Dunkelweizen for one of my next batches as well, which I plan on doing my first decoction mash, which should improve efficiency as well...but I digress...

Running the grain through the mill twice may improve an already good extract efficiency, but if the rollers are out of adjustment and insufficiently crushing the grain in the first place, running it through a second time wouldn't help much. Next time, just be sure to look at all your grain before you mash, and verify that there aren't a significant number of un-cracked kernels. The kernels should be split into at least thirds, if not quarters after they go through the mill. If your kernels are only split in half, that would lead to a low efficiency. The smaller the crush, the higher the efficiency. Once you start all-grain brewing though, if you get the crush too small, you will have a hard time sparging the grain, because it will be smaller than the holes in the false bottom.

Good luck!

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