Sour mix, also known as sweet and sour mix or bar mix, is a mixermade of lemon or lime juice and sugar syrup. It is an important partof many cocktails.
To make your own, mix one part heavy sugar syrup (3 parts sugar, 2parts water) with one part lemon juice, and add 2 egg whites per literof mix. The egg whites are optional, but will make the drinks slightlyfoamy. You may want to adjust the sugar/juice ratio to give the mixthe right balance of sweetness and tartness.