# Calculation question on backsweetening

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#### yeastluvr

##### Well-Known Member
I'm trying something new this year. I've always added white sugar or the occasional concentrate to cider to sweeten it after fermentation. It was suggested to me by the owner of the vineyard I picked my grapes to freeze some of the original juice, then use to backsweeten it. Question is, if I use 1.5 quarts of juice which is a 1.064 and fill my 3 gallon carboy to the top with .990 wine, what will the gravity be?

#### Yooper

##### Ale's What Cures You!
Staff member
Mod
HBT Supporter
I'm trying something new this year. I've always added white sugar or the occasional concentrate to cider to sweeten it after fermentation. It was suggested to me by the owner of the vineyard I picked my grapes to freeze some of the original juice, then use to backsweeten it. Question is, if I use 1.5 quarts of juice which is a 1.064 and fill my 3 gallon carboy to the top with .990 wine, what will the gravity be?

1.5 quarts of 1.064 + 3 gallons of .990 wine = 3.38 gallons of .998 wine.

OP
OP
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#### yeastluvr

##### Well-Known Member
Thanks Yooper. I'm actually going to add the 1.5 quarts to my 3 gallon carboy then add the wine to fill it to the top to make a total of 3 gallons "I will just save the leftover dry wine and drink it later. So with your calculations, I'm assuming it will be around a 1.00 or a bit over.

#### vNmd

##### Well-Known Member
1.5 quarts of 1.064 + 3 gallons of .990 wine = 3.38 gallons of .998 wine.

Its probably because I just finished my degree, but could you show your work (respectfully) I was wondering how to do calculations like this myself. I assume you are taking gravity points per gallon in some sort of algebraic formula.

#### mikder82

##### Active Member
64 gravity points in 1.5 quarts. 64/(4/1.5)= 24 points per gallon. 24/3 gallon= 8 points added per gallon. .990+.008=.998

#### Yooper

##### Ale's What Cures You!
Staff member
Mod
HBT Supporter
64 gravity points in 1.5 quarts. 64/(4/1.5)= 24 points per gallon. 24/3 gallon= 8 points added per gallon. .990+.008=.998

Yep. It's a simple ratio.

##### Well-Known Member
12 qts x .990 = 11.88
1.5 qts x 1.064 = 1.596
11.88 + 1.596 = 13.476
13.476/(12 qts + 1.5 qts) = .998

#### vNmd

##### Well-Known Member
Thanks Doc & all. I wish I was better at math. It has so many applications

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