Add the juice and sugar to a nonreactive saucepan. Gently heat until all of the sugar has dissolved and the juice is clear. Bring to a boil for 1 minute and remove from the heat. If not using as a syrup for dessert skip the next step.
If you would like to make a syrup for a cake or other dessert continue to boil until the liquid has reduced by half. This will yield a very sweet topping. Reduce the sugar by half when making the syrup if you would like to reduce the sweetness.
Pour through a fine mesh sieve into an airtight glass jar or bottle.
Notes
Yields about 2.5 cups of syrup. Can be stored in an airtight glass jar for about a month without opening. Once the jar has been opened then consume within 2 weeks. Can be frozen into ice cubes and stored in the freezer for up to 3 months.