Living in the northeast provides more opportunity to enjoy wines that are produced or improved by having residual sugar levels. This is primarily due to the varietals chosen for vineyards, that can be planted sustainably where winters are harsh. The French hybrids produce grapes higher in acid, lower in sugars and mostly require back sweetening to recapture balance in the glass. Our goals should always be to enhance our wines through any process we may employ. Back sweetening is a relatively simple process for home winemakers to employ. Following a few simple rules will help to ensure your results enhance your wine, and prevent undesirable effects like corks flying through your kitchen or bottles exploding in your car. Lets take a look at these fundamental steps.
Here is a simple rule for sweeting. 1.5 ounces of sugar will produce 1 brix or 1% residual sugar in a gallon of liquid. So if we want 6% residual sugar in a gallon, we would dissolve 9 ounces of sugar to add to the gallon of wine.
How much residual sugar is enough?
Lets take a sound approach here. Do small bench trials with various residual sugar levels to evaluate the varying flavor profiles. I would suggest 2% , 4%, and 6% samples. Make 12 ounce samples of each. These levels are generally an appropriate range for acceptable flavor profiles. Gather a few friends and have them help in evaluating the flavors profiles at the various residual sugar levels. Select the one that most enhances the wine.
To start, lets make sure all of our equipment is clean and sanitized. Preparing the wine to receive the sugar and prevent re-fermentation. Step one is to have the appropriate sulfite levels in the wine to be sweetened. Many spoilage organisms feed off sugars so we want to be certain they are not present. Adding 2 grams of potassium metabisulfite in 5 gallons is a good rule of thumb.
Step two: Adding potassium sorbate. PS prevents re-fermentation basically by not allowing yeasts to reproduce. I will spare you the micro biology lesson, and suggest a dose of 4 grams in 6 gallons as an effective dosage. Don't be heavy handed with PS as it can and will have an adverse influence on your wine if too much is present. Allow 12 hours for the wine to absorb the PS before adding the sugar.
Adding the sugar to your wine
Making a simple syrup is the best way to infuse the sugar into your wine. In as little distilled water as possible, dissolve the appropriate amount of sugar based on our formula above in boiling water. Allow the water to cool to room temperature, then add it to the wine while stirring. You can now bottle or return your wine to its bulk storage vessel.
There we have it, clean everything and your done.
Sweet or dry, experiment in enhancing your wines and always work in small trail samples until you reach a desired result. Keep good notes, so when you make a wonderful wine you will have the resources available to replicate the result.