In a small saucepan, bring the white wine and vinegar to a boil over medium-high heat. Rapidly simmer until the wine has reduced by 2/3, about 10 minutes. Set aside to cool.

Once the wine mixture is room temperature, whisk in the egg yolks. Transfer it to the top of a double boiler or a mixing bowl that fits snugly in your water pot. The bottom of the bowl should not touch the water, so pour some out if necessary. Bring the water to a boil, and set the wine-egg mixture on top. Whisk briskly over medium heat until the eggs have thickened to the consistency of mayonnaise, about 3 minutes. Remove from the heat and whisk in 1 tablespoon of the oil. Once combined, slowly drizzle in the remaining oil, whisking constantly, until smooth. Thin the sabayon with 2-3 tablespoons of water until the consistency is pourable. Add ½ teaspoon salt and taste for seasoning.