Orange zest

One US cup of orange zest weighs 96 grams (3.4 ounces). Going the other way, 100 grams is about 1.04 cups.

Fresh herbs and aromatics compared: cup weights side by side, the source behind each, and why they differ.

A teaspoon of finely grated orange zest weighs about 2 g and a tablespoon 6 g, the same as lemon zest: USDA's record for orange peel weighs a tablespoon at 6 g, and the Culinary Institute of America's chart gives the zest of one medium orange as 1 tablespoon, 6 g. A cup, if a recipe ever asked for one, would be 96 g (3.4 oz).

Orange zest is the thin, bright orange outer layer of the peel, rich in aromatic oil, grated off with a rasp-style grater so that the bitter white pith stays behind. It flavours cakes, muffins, scones, cranberry sauce, glazes, marinades, braises and cocktails, and it is often paired with orange juice from the same fruit. Recipes give it by the teaspoon or tablespoon, or as the zest of one orange.

USDA's record for raw orange peel weighs a tablespoon at 6 g, 96 g a cup, and this site publishes it. The CIA's conversion chart says one medium orange, zested, gives 1 tablespoon weighing 6 g; its ounce column says 0.25 oz, which is 7.1 g, so the chart disagrees with itself by a gram. Its row is a yield from one fruit rather than a measured spoon, so it is listed without a figure, but its grams match USDA's exactly. Confidence is medium: there is one direct weighing, and it matches lemon zest, on which two independent sources agree.

The physical check: grated orange zest is the same material as lemon zest, fine, moist, oily threads of peel, each about as dense as water, and it behaves the same way in the spoon. At 6 g a tablespoon, 0.41 g/mL, the threads fill about two-fifths of the spoon when it is loosely packed. Lemon zest on this site weighs 6 g a tablespoon by USDA and by Rose Levy Beranbaum alike, the same figure, which is what the physics expects for two zests grated the same way. Pressing the zest into the spoon makes it heavier, so spoon it in lightly.

Practical guidance: count 2 g a teaspoon and 6 g a tablespoon for finely grated orange zest, spooned in lightly and leveled. One medium orange gives about a tablespoon, 6 g, by the CIA's chart, and a large one more; when a recipe asks for the zest of one orange, a tablespoon is a fair measure. For a recipe that depends on orange flavour, such as an orange cake, orange rolls or cranberry orange bread, weigh the zest rather than counting oranges. Zest the orange before squeezing it, and grate just before use, because the aromatic oil fades once the peel is cut. Dried orange peel from the spice aisle is much stronger than fresh zest, and spice sellers suggest about a third of the volume in its place.