Proceed as for Simple Syrup, adding to the pan with the water and sugar thin strips of zest from 2 lemons or limes, or from 1 large orange or grapefruit. Simmer, covered, for 5 minutes. Once cool, you may add (1 cup lemon, lime, orange, or grapefruit juice). Strain and chill until needed. Store refrigerated for up to 1 month.