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Old 04-15-2013, 02:03 AM   #1
msh227
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Brewed a batch of Irish Red this morning and had some gravity issues I don't understand.

Recipe was pretty simple and my beer software had a preboil gravity of 1.046... My measurement was 1.042. The post boil gravity was suppose to be 1.056. I measured 1.040. Both samples were 70*

No clue why this happened. Pulled the sample when filling carboy thought it wasn't mixed well so I pulled another samplethis evening after it was mixed and had same reading. Maybe it settled from this morning to tonight?

Thoughts????
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Old 04-15-2013, 02:09 AM   #2
Yooper
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Quote:
Originally Posted by msh227 View Post
Brewed a batch of Irish Red this morning and had some gravity issues I don't understand.

Recipe was pretty simple and my beer software had a preboil gravity of 1.046... My measurement was 1.042. The post boil gravity was suppose to be 1.056. I measured 1.040. Both samples were 70*

No clue why this happened. Pulled the sample when filling carboy thought it wasn't mixed well so I pulled another samplethis evening after it was mixed and had same reading. Maybe it settled from this morning to tonight?

Thoughts????
Well, one of the measurements was wrong. This is no way a preboil gravity could have been 1.042, and the post boil 1.040.

If both samples were cooled to 70 degrees before reading them, then one or the other was just wrong.

The post boil gravity reading has to be higher than the preboil gravity- it just has to.
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Old 04-15-2013, 02:09 AM   #3
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How much top off water did you add?
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Old 04-15-2013, 02:14 AM   #4
msh227
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I agree. My preboil was a little less than recipe stated but okay no biggie but when my OG reading was less than preboil that threw me for a loop.

No top off water all grain batch 5 gallons, managed to hit that right on the money!!

Thinking about shaking carboy tomorrow morning to mix and taking another reading.
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Old 04-15-2013, 02:16 AM   #5
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Quote:
Originally Posted by msh227 View Post
I agree. My preboil was a little less than recipe stated but okay no biggie but when my OG reading was less than preboil that threw me for a loop.

No top off water all grain batch 5 gallons, managed to hit that right on the money!!

Thinking about shaking carboy tomorrow morning to mix and taking another reading.
I think your post-boil reading is correct, as if you didn't add top off water the wort would be homogenous. It must be the preboil reading that was wrong. Are you certain that the wort was cooled to under 100 degrees before using the correction table? That would make a huge difference. Or, if the preboil wort wasn't well mixed, that would also matter.
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Old 04-15-2013, 02:22 AM   #6
msh227
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Son of a gun think you figured it out for me. When I took my sample for preboil it pulled from mash tun run off and not at end after I was finished and mixed well (guess I won't do that again!).

Numbers still seem funny. Guess I have to chaulk this up to bad technique. Oh well I'll still get beer but dang low ABV with 1.040 OG. Oh well

Thanks for the input. Maybe I'll stop taking preboil gravity readings!
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Old 04-15-2013, 02:27 AM   #7
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The only way I could see your post boil being lower than pre boil is if you diluted your wort after boiling. Otherwise as Yooper said you just can't have a lower OG post boil than pre. As you have boiled off water concentrating the sugars in the kettle. Making a higher OG
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