gravity issues

DonWheelio said:

Hi all,



I just put down a batch and did a gravity read after the boil, but forgot to reread after I topped up the carboy with water and I've already pitched. My question is this:



Does anyone know how /is it possible to calculate the gravity knowing the old total volume, the old gravity and the total volume of liquid added?



old volume 3500ml, SG 1.070, 300ml added



Forgive me if this is in the wrong forum, it's my first post and I couldn't decide which forum area this fit best into.



Cheers!

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gstrawn said:

Yes it's not hard at all. 3500 mL x 1.070= 3745 points

3745 points / 3800 mls total= 0.9855

0.9855x 1.070 (OG)= 1.0545

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wilconrad said:

FYI, this logic is correct but the math is wrong. You have to convert the SGs into "Gravity Units".



You had 70 gravity units in your original 3500ml and the following equation applies:



V1 x GU1 = V2 x GU2



Applying to your values:



3500 x 70 = 3800 x GU2



So GU2 = 64.5 which corresponds to an OG of 1.0645

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