The next major step in the Concord wine adventure, assuming the wine will clarify from racking a few times over several months, will be stabilizing and sweetening. The plan is for this to occur in Jan or Feb 2012.
I have been researching the best way to sweeten wine, since Concord wine needs it.
After the wine is clear, it is time to stabilize and sweeten the wine. They both go together because adding sugar back to the wine might restart fermentation so killing the yeast when adding sugar is necessary.
Stabilize
Add stabilizing chemicals. In our case, 1/2 tsp. potassium sorbate (1 gram) and 1 crushed Campden tablet (per gallon wine) . Wait one day before sweetening so the yeast is inhibited.
Sweeten
Since sugar (granulated white sugar bought at any supermarket) and water can have contaminants, they must be boiled for at least 1 minute (3 minutes if you live over a mile above sea level). Boil (microwave works great. make syrup mixture in a large coffee cup) 1/2 cup water then add 1 cup sugar and stir until dissolved. Boil then let cool to room temperature. Add 1/2 cup syrup to wine, gently stir, and taste. Add another 1/4 cup, if necessary.
Put the airlock back on and let sit 1 to 4 weeks (longer the better) to make sure no fermentation starts.
I expanded on the subject here: winemaking: sweetening.
