- Two types of Thai ginger plants dominate Thai cuisine: galangal and grachai. While they are related to traditional ginger, each has its own distinct flavor. As galangal matures, it is often ground and used in curry pastes. Both types of ginger are usually peeled before cooking; grachai is often also slivered. Galangal may be slivered, minced, crushed, or otherwise utilized in the same manner as traditional ginger.
- Galangal, called "khaa" in Thai and sometimes "greater galangal" in English, is known to horticulturists as Alpinia galangal. While it is not commonly available fresh in supermarkets in the United States, it can be found in international or Southeast Asian produce markets. Dried, powdered, and pickled forms are also available. However, like traditional ginger (Zingiber officinale), the fresh version has more depth of flavor than other versions. Pickled versions should be rinsed before use. Australian restauranteur and Thai cuisine chef David Thompson recommends soaking them in sugar water in order to nullify the taste of the chemicals used to preserve the galangal. Fresh galangal is similer to traditional ginger in shape and size, but can vary in color from gold to dark red as it matures. The skin also becomes thicker as it gets older.
- Grachai, sometimes also called kachai in Thai, is also sometimes called "lesser galangal" or even simply "rhizome" in English. These roots are long, small, and yellowish, and branch off like fingers. It can be found in Chinese markets under the name "Chinese keys." The flavor is unique, even among ginger plants. While Thai food cooked in the United States often substitutes traditional ginger for galangal with good results, grachai has a taste that cannot be substituted. It is most commonly used in soups, stews, and curries that involve seafood. It is more difficult to find fresh than galangal, but can be found frozen or pickled. As with galangal, pickled grachai needs rinsing before you use it in recipes so that its true flavor is allowed to shine through in your finished dish.
- In areas with mild winter climates, galangal and grachai can be grown outdoors as perennial plants. In colder climates, both can be grown in potted plants and moved indoors over the winter. Since both are in the ginger family, they function similarly, producing decorative foliage aboveground and culinary rhizomes below ground. Harvest small amounts of both rhizomes at any time for culinary use as needed. To plant, simply place either a small piece of fresh galangal or a finger of fresh grachai in some soil at a 1 inch depth. Ideal soil is neutral and loamy, although galangal and grachai should grow satisfactorily as long as the soil is not too heavy and dense with clay.