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Old 07-24-2010, 06:57 PM   #1
Feb 2010
London, ON
Posts: 76

Does anyone know a simple way to get a pre-boil gravity reading when doing a split boil? I'm in an apartment and can only manage to used two 4-gallon pots for my all grain boils. Assuming that its next to impossible to have both pots at the same gravity, is there a simple way to get an accurate pre-boil gravity?

The only thing I can think of is to take an equal amount of both worts and test that, but does anyone have another method that works?
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Old 07-24-2010, 10:17 PM   #2
malkore's Avatar
Jun 2007
Posts: 6,922
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I'd say take gravity of each wort, and use the average. I never took pre-boil gravity until I got my refractometer, which was the only time I did split boils like you're doing.

I also did half my runnings into each pot to keep them fairly equal (for hop utilization, etc).
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Old 07-26-2010, 04:10 PM   #3
shroomzofdoom's Avatar
Dec 2009
Piscataway, NJ
Posts: 517
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Not sure if you are doing All Grain or Extract/Partial? If AG, it's actually a bit easier to do this.

I too have had issues keeping both pots at the same gravity. When lautering, I would usually run 1-1.5G into each pot for the first runnings, then do the same with the second runnings for 2 G--splitting the runnings evenly. Could never get the same SG in each pot.

Recently I started collecting my first and second runnings into my clean primary fermentation pail and mixing them there. (assuming nothing is occupying said pail) It holds about 6.5G, so there's an extra gallon or so for you to collect in another pot. Just stir with a spoon, then transfer equal amounts to each kettle. Take that last gallon and split that evenly and you should be spot on.

When I did Extract, I would just measure everything into equal parts and split them, but this didn't seem too accurate. Like I said, easier in an AG for me.

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Old 07-26-2010, 06:40 PM   #4
david_42's Avatar
Oct 2005
Oak Grove, Oregon, USA
Posts: 25,599
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Not really. You need to calculate the total points: ((Volume A x Gravity A) + (Volume B x Gravity B)/( Volume A + B)

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