In a pitcher, stir together the vodka, orange juice, sparkling water, if using, vermouth and bitters. Pour into 4 iced-filled old-fashion glasses and garnish with a sprig of fresh thyme and an orange slice.
In a pitcher, combine the oregano, thyme and rosemary. Using a wooden spoon, gently crush the herbs. Add the vodka and cover the pitcher with plastic. Store at room temperature for at least 24 hours. Strain before using.