Ginger Syrup

I just bought the Alinea Group's newest non-alcoholic cookbook—it's amazing, btw—and found myself with some extra ginger syrup after trying out one of their cocktails. So I HAD to add it to a margarita with watermelon. And presto: Watermelon Ginger Margarita.

1 large hand of ginger.
granulated sugar, as needed

Peel the ginger and process through a juicer. Refrigerate the ginger juice for an hour or two to let the starch settle. Decant the juice into another container and weigh the juice. Measure half that amount of granulated sugar. [For the math-challenged, if you decant 150 grams of ginger juice, you'll need 75 grams granulated sugar.] Add the ginger juice and sugar to a blender and blend on high until all the sugar is dissolved.