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02-04-2010, 06:13 PM   #1
Frank99
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 Gravity Calculation Help

I just did my 1st all-grain batch and have a question:
I have a gravity reading from right after the sparge of say 1.04.
I then boiled the 8 gallons of wort down to 5 gallons.
Unfortunately, I don't have a gravity reading after the boil as my hydrometer broke. How can I figure out the post boil gravity?

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02-04-2010, 06:38 PM   #2
VictorWI
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The calculations I've seen for evaporation are:

FinalGravity = (InitGravity - 1) * 1000 * InitialVolume / FinalVolume / 1000 + 1

(1.040 - 1) * 1000 * 8 / 5 / 1000 + 1

Which is 1.064.

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Last edited by VictorWI; 02-04-2010 at 06:39 PM. Reason: typo

02-04-2010, 11:09 PM   #3
Frank99
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Thanks! Surprisingly that puts me right where I should be.

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