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Old 08-01-2011, 05:13 PM   #1
Sokrateez
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Default Strange gravity readings?

So I have an issue. I brewed last night, and took a gravity reading pre-boil and post-boil (well actually the post-boil was once it was dumped in the fermenter), but the post-boil was not what I expected. The pre-boil was 1.034, corrected for temp, with around 7.5 gallons of wort. After I dumped around 6 gallons in the fermenter, took a gravity reading and corrected for temperature, I mysteriously got a reading of 1.032? How is that possible?

I'm thinking one of 3 scenarios: I took the first reading wrong, and actually got a really low efficiency, I took both readings right (somehow?) and this beer is just going to be about 18 points too low (and about 2% abv short), or I got the second reading wrong and everything is actually going to be alright.

e: I guess the only sure(ish) way to find out is by taking the final gravity and multiplying by 4 (figuring an attenuation of 75%) to figure out the alcohol and OG.



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Old 08-01-2011, 06:50 PM   #2
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Can you include the recipe so we can get a better feel for the target gravities?


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Old 08-01-2011, 07:36 PM   #3
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Sure,
7 lbs 2-row
2 lbs caramel 60
.25 lbs chocolate

.25 oz Galena at 45 minutes remaining
.25 oz Galena at 30 minutes remaining

Mashed 14 quarts at 154f for 60 minutes, batch sparged with 6 gallons, collected 7.5 gallons with a gravity of 1.034.
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Old 08-01-2011, 08:18 PM   #4
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Check your hydrometer in some 60F water and make sure it reads close to 1.000.

You may have cracked it between readings.
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Old 08-01-2011, 08:44 PM   #5
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Just checked it now and that's not it. Any other thoughts?
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Old 08-01-2011, 08:47 PM   #6
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What temp was the preboil wort when you measured the gravity?
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Old 08-01-2011, 10:06 PM   #7
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It was 1.031 at 83f, which is where I got 1.034 from.
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Old 08-02-2011, 01:02 AM   #8
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1. Check the thermometer you used in the mash--at mash temp, if possible.

2. Buy a second hydrometer. I have had very similar things happen a few times in the past and find that keeping a backup usually scares my primary hydrometer straight.

It's funny, though. This exact thing happened to me about a week ago. The second runnings measured the same pre- and post-boil. I can only assume I screwed up the preboil reading. Doesn't it chafe your brain that you'll never know? I can hardly stand it.
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Old 08-02-2011, 01:12 AM   #9
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Yeah, it does lol. The thermometer is off by few tenths of a degree, I know that, and my hydrometer IS the second one, the first broke on my first brew day! Lol.

Anyway I suppose I'll see what the final gravity is and go from there. The yeast is going nuts right now anyway. It'll make beer! So it's all good.


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