Two teaspoons of simple sugar (is that 1 teaspoon of sugar dissolved in 1 teaspoon of water?) You might want to taste the wine to see if it is as sweet as you want it. To me back sweetening might mean adding 4 oz of sugar dissolved in either wine or water. Four ounces of sugar will raise the gravity of a gallon by about 10 points and if your wine was at say 1.000 then it would be at 1.010 and that is semi sweet (though how sweet will depend on the level of acidity and alcohol in the wine). BUT while I tend to ASSUME that a very dry wine or mead will need about 10 points of sweetener, bench testing is always the best approach. (in other words, if 4 oz is my default, I might add to 20 ml enough sweetener to be equivalent of 2, 3, 4, 5 (even 6 oz) and if the test suggests that the best option for THIS wine is between 2 and 3 oz, then I repeat the process adding the equivalent amount of sugar to each identical sample, of say, 2.2, 2.4, 2.6 and 2.8 oz (I still have some of the 2 and some of the 3 oz sample... and I see which hits the "sweet spot" (pun very much intended!)
