Galangal (kha — Alpinia galanga) and ginger (khing — Zingiber officinale) are often treated as interchangeable by cooks outside the Thai tradition. Thompson is explicit on their distinction — they are not interchangeable, they are not similar in flavour, and they function very differently in Thai preparations. Galangal in Thai cooking is a primary structural aromatic in curry pastes, soups (tom kha, Entry TH-10), and certain sauces — it is used in large quantities and contributes a distinctive resinous, slightly medicinal, piney character. Ginger is used in different preparations and at different quantities — it is not a substitute for galangal but a separate ingredient with separate applications.
**When to use galangal:** - All central Thai curry pastes (red, green, massaman, panang, yellow, gaeng kua). - Tom yum (Entry TH-09), tom kha (Entry TH-10). - Most standard Thai soups. **When to use ginger:** - Khao man gai dipping sauce (Entry TH-24). - Gaeng hang lay paste (Entry TH-32). - Stir-fries where fresh, sharp ginger heat is required. - Miang kham (Entry TH-33). **When both are used:** Gaeng hang lay uses both — ginger dominant, galangal supporting.
David Thompson, *Thai Food* (2002); *Thai Street Food* (2010)