Galanga or galangal (kah): This robustly pungent member of the ginger family is the primary ginger used in Thai cooking and is, therefore, sometimes referred to as "Siamese ginger." It is also called "greater galanga" (there is a very different relative called "lesser galanga") and "laos root." Fresh galanga has an ivory or very pale yellow color and its growing tips are tinged pink, much like young ginger. Denser, firmer and even more knobby than common ginger, the rhizome is also rounder, marked with concentric rings every half inch apart and has no skin to be peeled. Tasting nothing like ginger, its hotter and sharper bite combines with a tangy spicy flavor which, to some people, is reminiscent of hot mustard. To others, it tastes medicinal and indeed it is.
Like other members of the ginger family used in Thai cooking, galanga's pungent spiciness freshens the taste of seafood, making it a valued herb in seafood salads and soups. For salads, slice the root as thinly as possible, then stack several slices at a time and cut into very fine slivers; for soups, thin slices are simmered to flavor the broth. Galanga is also an essential ingredient in most Thai curries and is chopped and pounded to a paste with other paste ingredients. When buying galanga, select a young rhizome that is as light in color as possible with pinkish shoots and few or no brown spots. Avoid large, fat roots, as these can be very hard and woody, making it almost impossible to cut. Sometimes a piece you get will be tender at the tips and woody further down; save the tender end for salads and use the more fibrous section for seafood soups. Store fresh galanga wrapped with a paper towel inside a plastic bag in the refrigerator; it will keep for two to three weeks.
If you are not able to find fresh galanga, frozen roots imported from Thailand are available in most Southeast Asian markets. These roots may have an orangish brown color, because they are a slightly different variety, but they are the next best thing to fresh. For pounded chilli and curry pastes, the frozen roots grown in the tropics give a fuller range of flavors than the fresh ones grown in temperate zones.
Galanga is also sold in slices packed in brine in glass jars; rinse first before use. (Beware of jars confusingly labeled as "galanga" or "galingale," which actually contain the slender, finger-shaped "lesser galanga") It is most commonly available in dried woody pieces in plastic bags. The dried form is acceptable for soups, but lacks the fresh flavor required for seafood salads, in which case, it can be substituted with fresh ginger. The dried pieces come in handy for recipes that require ground, roasted galanga. Avoid the powdered kind unless you are not able to find fresh, frozen, bottled or dried pieces.
If you live in a frost-free area, try growing galanga to assure yourself a continual supply of fresh rhizomes. Buy a very fresh rhizome with unbruised pinkish shoots and plant shallowly in moist, well-drained soil. Like ginger, it grows into a lovely tropical plant for the garden, producing sweetly fragrant, white orchid-like flowers atop lush four-foot stems over many weeks in late summer and autumn. It grows very vigorously once established.
by Kasma Loha-unchit in Dancing Shrimp: Favorite Thai Recipes for Seafood. See pages 58 & 59.