Navels, a member if the sweet orange family, is characterized by its thick skin and an embryonic fruit within the fruit. The flesh and juice of navels are delicious but can turn bitter when exposed to air, so these are best eaten out of hand, especially because they are seedless, or served soon after peeling. You can, however, use their zest to add a floral, citrusy accent to dishes. Their juice is also delicious for drinking or to use in mariandes, vinaigrettes, and sauces.
1 medium = 6 to 7 Tbs. juice and about 2 Tbs. lightly packed zest if grated on a rasp-style grater
You can substitute Valencias or any other sweet orange.
Navel oranges are generally in season from November through May. Choose oranges that feel heavy for their size (signaling they're juicy) with a skin that does not feel loose.
Oranges are fine if stored at room temperature for a few days, but they'll last longer and taste better if refrigerated.