
Orange zest is the colored outer layer of an orange’s peel, prized for its aromatic essential oils.
A twist expressed over the surface gives a bigger first impression and fades faster. Tangerine or blood orange zest changes the shade of the aroma. Orange bitters put the top note in from a bottle and taste of spice as well as orange.
Orange twist
A wide strip of the same layer, squeezed over the drink so the oil lands on the surface; it perfumes the approach to the glass; grated zest perfumes the drink itself.
Dried orange peel
A different ingredient — tea-like and slightly bitter, used in infusions and bitters. The fresh volatile oil, the whole reason you twist a peel over a drink, is long gone from it.
Zest to order. Grated zest dries out within the hour and loses the volatile part first, so a bowl prepared at the start of service is dust by the middle of it. Whole fruit keeps two or three weeks refrigerated, and unwaxed fruit zests cleaner.