Zest is the colored portion of the citrus peel or rind that is grated. The white portion, or pith, is bitter and should be avoided. Fruit should be zested before squeezing, which is why zest is sometimes listed in the ingredient lists slightly out of order from where it’s added to the recipe. However, if you need only the juice but want to save the peels for another use, you can freeze the peels in a reclosable freezer bag and then zest them straight from the freezer when needed. Be sure to wash the fruit in liquid detergent and hot water and rinse it well or it will add a bitter taste to the recipe. For extra finely grated zest, after grating it with a Microplane grater, use a chef’s knife to chop it to a fine consistency, or process it with some of the sugar in the recipe.