Let's say I'm making a gallon of blackberry wine. When I start the primary fermentation the O.G. is 1.090, and I know from past experience with my blackberry wine recipe it will ferment down to dryness at 0.990. After 5-7 days the specific gravity in primary has fallen to 1.010, so I rack it off into a sterilised secondary demijon. Let's say, however, that the level in the secondary demijon is about 500ml short of the neck, so I want to top it up with about 500ml of sugar solution.
What is the correct S.G. of the sugar solution to add, without affecting the gravity calculation from the O.G.?
A few times in the past when I've done this, I thought it was correct to add sugar solution that matches the current S.G. of the wine (1.010 is about 35g/l of sugar)
Recently, I've had pause to re-think and reasoned that the wine has already fermented from 1.090 down to 1.010, so already has about 10.5% alcohol. That means, I should have added a sugar solution that matches the O.G. (1.090 is about 245g/l of sugar).
Then I've thought again that maybe I should add a sugar solution that is the difference between 1.090 and 1.010 i.e. 1.080 (about 218g/l).
Can someone explain what is the correct approach?
What is the correct S.G. of the sugar solution to add, without affecting the gravity calculation from the O.G.?
A few times in the past when I've done this, I thought it was correct to add sugar solution that matches the current S.G. of the wine (1.010 is about 35g/l of sugar)
Recently, I've had pause to re-think and reasoned that the wine has already fermented from 1.090 down to 1.010, so already has about 10.5% alcohol. That means, I should have added a sugar solution that matches the O.G. (1.090 is about 245g/l of sugar).
Then I've thought again that maybe I should add a sugar solution that is the difference between 1.090 and 1.010 i.e. 1.080 (about 218g/l).
Can someone explain what is the correct approach?
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