Cymbopogon citratus — lemongrass — is the most widely used aromatic in Thai cooking and the ingredient most identified internationally with Thai cuisine. Thompson uses it in three different forms across his preparations, each producing a different aromatic contribution: 1. **Bruised and added to soups and braises:** The intact stalk, struck firmly with the back of a knife or a pestle, ruptures the cell walls and releases aromatic compounds into the surrounding liquid during simmering. Not eaten. 2. **Thinly sliced for pastes and salads:** The white stalk only (the bottom 10–12cm, where the essential oil concentration is highest) sliced into paper-thin rounds — added to raw preparations (miang kham, Entry TH-33; certain salads) or as a component in curry paste pounding (Entry TH-01). 3. **Pounded to a paste:** In curry pastes, the sliced lemongrass is reduced to a fibre-free component through pounding — its citral compounds integrated into the paste's fat phase.
**The white stalk — anatomy:** The entire lemongrass plant is edible, but only the white, inner stalk is aromatic enough to use. The outer 2–3 layers of the stalk are fibrous and largely inert. Remove them until the white, slightly moist inner stalk is exposed. The inner stalk, thinly sliced, should smell intensely of citral — a combination of geranial and neral, the two isomers that produce lemongrass's characteristic citrus-floral aroma. **Storage:** Fresh lemongrass: refrigerate in a dry cloth for 2–3 weeks. Freeze in whole stalks for 6 months (slice or pound directly from frozen — freezing partially breaks down the cell walls and makes the aromatic compounds slightly more accessible). **The bruising technique:** A firm, single strike with a heavy knife back or a rolling pin — enough to crack the stalk without fully separating it. A lightly tapped stalk that shows no cracking has not been adequately bruised and releases its aromatic compounds more slowly.
David Thompson, *Thai Food* (2002); *Thai Street Food* (2010)