This, my friend, is entirely up to you and your taste buds. Cocktail recipes generally call for 2-3 dashes (somewhere between 1.5 and 2.5 mL). Our suggested serving size is 1/2 teaspoon (around 2.5 mL), but you may want to add more to sparkling water or beer if you prefer a more intense flavor. Personally, we add anywhere from 3-5 dropperfuls of bitters to a 12 ounce glass of sparkling water or beer, depending on how spicy we're feeling.