Many types of wines need a little sugar boost near bottling time. Any sugar added before fermentation will not have an effect on the sweetness of the wine since the sugar is consumed by the yeast.
The wine needs to be stable before sugar is added, otherwise fermentation may start up again. It is best to sweeten wine just after stabilization is done; i.e stabilize, wait 24 hours for yeast to die off, sweeten.
The specific gravity (SG) of unsweetened wine is near 1.000 or a little below (0.996 for example). To raise SG by 0.010 it takes about 30 g/L of sugar added which translates into about 1/2 cup.
Since sugar and water can contain contaminants, they need to be boiled for at least 1 minute.
When sugar is mentioned, it is the granulated white sugar commonly bought at a grocery store.
Also note that wine takes up to 24 hours to fully absorb the sweetener.
- granulated white sugar
Make a simple syrup from two parts sugar to one part water and stir until the sugar is completely dissolved and the liquid is clear. Do this in a small saucepan. Use boiling water for making the syrup for sanitary reasons.
The syrup can be made in a microwave. Boil the water in the microwave then add the sugar and boil it for 1 minute. Stir to dissolve sugar then let cool.
The syrup needs to be at room temperature before adding to wine.
Add the syrup in stages to the wine and stir well to integrate it. Start with 1/2 cup of sugar solution.
Do not add sugar directly to a finished wine. More than likely it contains a great deal of absorbed carbon dioxide and adding sugar crystals will cause it to erupt like a volcano with foam.
After sweetening, reattach the airlock and let the wine sit another 3 to 4 weeks to be sure it doesn't start refermenting.
Corn sugar in not quite as sweet as cane sugar you buy from the store, but seems to give the wine a more crisp, cleaner flavor. This would be a good choice for most white wines or more generally, wines with a lighter, more delicate flavor.
Honey can also be a be used to sweeten your wine. For example, use raspberry honey to sweeten a raspberry wine. Very effective.
Wine conditioner that makes sweetening your wine very simple. It is a heavy syrup with stabilizer already incorporated into it. You just add to taste.
Wine concentrates quite often are appropriate as a sweetener and will also enhance the wine's flavor. Also, consideration should be given to the fact that the wine's acid level will be increased by the natural acids in the concentrate.
Fresh Fruit Juices can be used in the same way as concentrate. Grape, apple, pear all work very well. Fresh fruit juice is quite often the best choice when sweetening harsher wines such as elderberry.
Artificial Sweeteners need to be mentioned here as a precaution. Sweeteners such as Equal and Sweet 'N Low do not bond well on their own with liquids. Pop manufacturers use binders to keep these artificial sweeteners suspended. If added to a wine that has been stored these types of sweeteners will need to be stirred up off the bottom before serving.
By all means experiment. If you have a 5 gallon batch, take off a measured quart and add a measured amount of sweetener of your choice to it. I you like the results, multiply your efforts to the rest of the batch. If not, pour it back in with the rest and start all over.