This can be made in different proportions, the most common being one part sugar to one part water. This recipe yields a richer simple syrup, which we prefer, since it keeps better and less is needed to sweeten a drink. Less syrup means less dilution of the other ingredients, which is especially important for cocktails.
Combine in a saucepan:
Cook over low heat, stirring occasionally, until the sugar has completely dissolved. Let cool, then chill until needed. Rich simple syrup will keep in the refrigerator for 6 months; a weaker one-to-one syrup will keep for 1 month.