Home Brew Forums > Dilution to wort and how water effects OG

08-09-2012, 12:57 AM   #1
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 Dilution to wort and how water effects OG

Hi I'm new to the site although I've been brewing for quite some time. I have a quick question around dilution and the approximates on the gravity reading. I had a gravity reading of 1.078 after boil. Making an IPA. I diluted about 5 gal of wort with 32 oz of water but forgot to take another reading. Dumb I know.

Anyone know how much the OG would've dropped by/lowered to?

Thanks
Matt

08-09-2012, 01:28 AM   #2
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Quick check with my software say 1.074

08-09-2012, 01:40 AM   #3
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640 oz (5 gal) times 1.078 equals 689.92
32 oz times 1.000 equals 32
689.92 plus 32 equals 721.92
721.92 divided by 672 oz equals 1.074

08-09-2012, 02:04 AM   #4
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Quote:
 Originally Posted by ktblunden 640 oz (5 gal) times 1.078 equals 689.92 32 oz times 1.000 equals 32 689.92 plus 32 equals 721.92 721.92 divided by 672 oz equals 1.074
Thanks!

08-09-2012, 02:29 AM   #5
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An alternate approximation would be to take the original volume and divide it by the final volume to get a reduction factor. Then multiply the reduction factor by your initial points value ((SG-1)*1000). So,

RF = 5 gal/5.125 gal = .976

74 * .976 = 76

Convert back to SG is 1.076

I know it's different than what others have said, but just wanted to throw out a different way to do it that has always worked for me.
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08-09-2012, 02:50 AM   #6
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Thanks. You misstated the 5.125 rather than 5.25 since 32 oz is .25 of 128, and 76 rather than 78 OG, but the actual calculation looks correct.

Appreciate everyone's help!

08-09-2012, 03:08 AM   #7
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Terribly sorry for that miscalculation. Using 5.25 gallons I also get 1.074.
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08-09-2012, 03:10 AM   #8
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Quote:
 Originally Posted by nukebrewer 74 * .976 = 76
Haha, I think I was drunk when I wrote that. That just plain doesn't make any kind of sense. I meant 78 instead of 74.
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08-09-2012, 11:25 PM   #9
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Or just type in 5.25 into our spread sheet

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regularly brewed ales:
Hopostle single IPA
Hopostle double IPA
Brooklynn Brew Saison (every summer)