To make a white sangria, pour a bottle of chilled white wine into a pitcher. Thinly slice 1/2 orange, 1/2 lemon, 1/2 lime and 1/2 grapefruit and add to the wine. Pour in 100ml cognac and 2 tablespoons of sugar, stir until the sugar dissolves. Add ice and soda water to taste. SALUD!