what is a lime zest
Zest is the thin, brightly colored outer layer of a lime or lemon that is generally used to add bright flavor to all sorts of recipes. Remove this intensely flavored, citrus-oil-filled skin of your lime or lemon with a fine grater or citrus zester, being careful not to grate into the spongy white layer beneath. The white layer is bitter and unpleasant, but the zest itself holds the essence of the citrus flavor. Lemon or Lime Zest Desserts.