To freeze orange zest, first wash the fruit thoroughly to remove dirt and pesticides. Use a grater to zest the orange skin, avoiding the bitter white interior. Place the grated zest in an airtight container and put it in the freezer.
It is convenient to freeze the zest in premeasured amounts to easily unfreeze it for recipes. To do this, measure out teaspoon servings of the zest and place on a sheet of parchment paper. Put the sheet in the freezer for one hour. When the zest is stiff, take the servings off the sheet and move to a container. Place the container in the freezer.