
Orange is the edible citrus fruit of the species Citrus × sinensis, a hesperidium supplying both sweet juice and aromatic peel.
Juicy and rounded on the palate, the pulp is sweet with mild acidity, while the peel finishes on a bright, oily citrus aroma led by limonene.
Bartenders twist or squeeze a strip of peel over the surface to express its volatile oils as an aromatic accent, drop the twist in as garnish, or press the pulp for a sweet, low-acid mixing juice; the juice is best used fresh and dosed as a lengthening volume.
As a peel or twist the sweet-orange oil is a defining aromatic that another citrus cannot truly replace — a lemon or lime twist gives a different scent. As a bulk juice it can be partly rebuilt with a less-sweet citrus balanced with sugar and a touch of lemon or lime for acidity, though the profile shifts.
Bitter orange (Seville orange)
Sweet orange (Citrus × sinensis) is sweet and eaten or juiced fresh, whereas bitter orange (Citrus aurantium) is a separate species that is sour and bitter, used mainly for marmalade, liqueurs and flavourings rather than eaten fresh.
The sweet orange is a hybrid thought to descend from a cross between pomelo and mandarin. Each fruit carries a coloured outer rind rich in aromatic essential oils, a white spongy pith beneath it, and segments of juice-filled pulp; the peel's oil is dominated by limonene.
Fresh-squeezed juice oxidises and loses aromatic freshness quickly, so it is best used soon after juicing; cut fruit should be refrigerated.
The sweet orange originated in East Asia — the region of southern China, northeast India and Myanmar — and was spread westward through cultivation.