The distinction between galangal and ginger is one of the most important and most frequently misunderstood ingredient distinctions in Southeast Asian cooking. Both are rhizomes; both share a family (Zingiberaceae); both are used in many of the same preparations. But their aromatic profiles, flavour contributions, and culinary functions are as different as parsley and tarragon — related in category, distinct in character.
**Ginger (khing — Zingiber officinale):** - Primary aromatic: [6]-gingerol (in fresh ginger) — warm, sharp, slightly citrusy, with a pungent heat that is different from capsaicin heat. - In cooking: ginger's heat is produced by the gingerol compounds, which are converted to zingerone (milder, slightly sweet) by cooking heat and to shogaols (more intense, pungent) by drying. This means fresh ginger is milder in a cooked preparation than dried ginger. - Thai applications: ginger is used in specific preparations (khao tom — Entry TH-35, certain noodle soups, the sauce for khao man gai — Entry TH-24) and is deliberately avoided in others (curry pastes where galangal is specified, tom kha — Entry TH-10 where galangal is the named ingredient). **Galangal (kha — Alpinia galanga):** - Primary aromatics: galangin (flavonoid), diarylheptanoids, 1,8-cineole (camphor-eucalyptus note), and several sesquiterpenes. - The galangin-1,8-cineole combination produces the characteristic resinous-medicinal-camphor note that is immediately recognisable as galangal and cannot be produced by ginger. - In cooking: galangal's aromatic compounds are more stable under heat than ginger's — galangal in a long-cooked curry retains its character more consistently than ginger would. **Where each is used:** - Galangal: all Thai curry pastes (Entry TH-04, TH-05, TH-06, TH-50), tom kha (Entry TH-10), tom yum (Entry TH-09), gaeng hang lay (Entry TH-32), all preparations where the resinous-medicinal note is intended. - Ginger: khao man gai dipping sauce, nam jim sauces, certain soups, preparations brought to Thailand from the Chinese culinary tradition. **Visual distinction:** Fresh galangal is paler (cream to pale yellow), with a smooth skin and a much harder, more woody texture than ginger. Fresh ginger is more golden-yellow, more papery-skinned, and significantly softer. When sliced: galangal is visibly harder and denser.
David Thompson, *Thai Food* (2002); *Thai Street Food* (2010)