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Old 10-08-2012, 12:50 AM   #1
jamesdawsey
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Default Uncommonly Low Gravity?

Alright, so today's brew day has ended with an unexpected twist. If you have any ideas as to what might cause an unusually low OG I am all ears. Here's how it went down. I've attempted to do a twist on a personal favorite. I've brewed it before with excellent results. It's Vinnie Cilurzano's recipe for Pliny the Elder. I mash using 1.25 quarts water per pound of grain. So for 14.45 lbs. of grain I added 4.5 gallons of water at 158*F. The recipe is below. Today I brewed this again.... and my measured OG ended up being 1.020 at 86*F. That ends up at 1.023 SGU. The mash didn't stick, I got an ordinary amount of wort out of the lauter tun. My mash temp was 152*F and I mashed for 80 min. (Boiled a prickly pear mead in the meantime). After the boil I ended up with an uncommonly low amount of wort, but I'm pretty sure that should increase the density of the wort; therefore raising the specific gravity. I'm at my wit's end and am feeling a little guilty as today's brew day was not beer for me, but one that my friend paid for so that I could walk him through the process and show him how it's done. The recipe is below. I believe I've given all the useful facts as well as some useless information. And if you've made it this far in the post, thanks already!


Target Stats: Measured Stats:
OG: 1.072 Actual OG: 1.067
Extract efficiency: 75% Real Efficiency: 84%
IBUs: 90-95 Actual IBUs: 265
ABV: 8.2% Actual %ABV: 7.5%
SRM: 7

Malts:
13.25 lb – 2-row pale malt
0.6 lb. – Crystal 45 malt
0.6 lb. – Carapils (Dextrin) malt
0.75 lb. – Dextrose (corn) sugar

Hops:
90 min - 3.50 oz. Columbus 13.9% AA
45 min – 0.75 oz. Columbus 13.9% AA
30 min – 1 oz. Simcoe 12.3% AA
0 min – 1 oz. Centennial 8% AA
0 min – 2.5 oz. Simcoe 12.3% AA

Dry hops:
12 - 14 days = 1 oz. – Columbus
1 oz. – Centennial
1 oz. – Simcoe
5 days to go in dry hop = 0.25 oz. Columbus
0.25 oz. Centennial
0.25 oz. Simcoe

Yeast: WLP001 or Wyeast 1056 (2nd attempt: WLP530 & Wyeast Brett. B.)

Directions:
Mash grains at 151-152*F for 60 min. Mash out at 170*F and sparge. Collect 8 gallons of runoff, stir in dextrose, and bring to a boil. Add hops as indicated in the recipe. After a 90 minute boil, chill wort to 67*F and transfer to fermenter. Pitch 2 packages of yeast or a yeast starter and aerate well. Ferment at 67*F until fermentation activity subsides, then rack to secondary. Add first set of dry hops on top of the racked beer and age 7-9 days, then add the second set. Age five more days then bottle or keg the beer.

Today's Notes / sources of error:
1) I sparged with 2 gallons room-temperature water. I've done this before with good results, so I stopped worrying about sparge temp.

2) I'm brewing in a new boiling kettle with a wider mouth. I understand that this explains the higher evaporation rate, but I do not expect that it would lower the gravity.

3) I mashed for 80 minutes instead of 60 min. This couldn't hurt... could it?

4) My thermometer is a cheap digital one and it's got a whimsy that is entirely its own. I've checked it though, and when it gives a steady reading it is properly calibrated.

5) After the boil I ended up adding sterilized water to bring the volume up to a solid 5 gallons. This certainly would lower the gravity, but I did the same thing last time I brewed this one, and I hit 1.067 SGU.


Any and all ideas will be most appreciated! Thanks!
James

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Old 10-08-2012, 12:54 AM   #2
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Please feel free to check/correct my math. I think it's all right, but what do you think?

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Old 10-08-2012, 01:34 AM   #3
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Is your thermometer accurate?

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Old 10-08-2012, 01:42 AM   #4
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You process looks ok.

>>5) After the boil I ended up adding sterilized water to bring the volume up to a solid 5 gallons. This certainly would lower the gravity, but I did the same thing last time I brewed this one, and I hit 1.067 SGU.


Did you did mix in this water, before you took the gravity reading?

I guarantee you, adding water and not mixing it in, will distort gravity readings. The water does not automatically mix itself.
I have experienced this first hand.

The only other possibilities are - your thermometer was way way off, or the grain was poorly milled.

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Old 10-08-2012, 11:16 PM   #5
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The reading was steady on the thermometer when I got the 86*F reading and gravity. Also, if my math is correct then the wort would have to be 207*F to give a hydrometer reading of 1.020 with an actual specific gravity of 1.061. That's not a discrepancy that's easy to overlook with your hands on the kettle. I can't be certain (Like I said, I definitely need a new thermometer), but I think my thermometer gave me an accurate reading.

@Arclight: I think you may be on to something. I did not mix in the water before my gravity reading. Having not done this before, it didn't occur to me. At the very least this is a gleaming light of hope. BTW, this evening the fermenter is bubbling away quite healthily, and boy does it smell good! I will have to post back and let you know how it turns out.

I think Arclight's probably right. Any other thoughts would be most appreciated!

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Old 10-08-2012, 11:17 PM   #6
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I'm with Arclight on this one too, we see the same complaint all the time in the extract brewing threads.

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