Though often referred to as a root, ginger is actually a rhizome of a tropical plant. Fresh ginger's tangy freshness, light spiciness, warmth, and mellow sweetness complement a range of dishes, from sweet to savory. A main flavoring in Chinese cooking, ginger is widely used in Indian, Japanese, and Thai cooking as well.
Fresh ginger is also equally at home with such an everyday American ingredient as maple syrup and can be infused into milk and cream to make a tangy custard or ice cream. Fresh ginger also adds a nice counterpoint when cooked with vegetables (it's lovely with tomatoes) and it has a natural affinity to meats, poultry, and fish. Though fresh ginger packs the most punch, it comes in a variety of forms: pickled, dried and ground, and crystallized; the latter two forms are used primarily in baking.
Ginger's aroma, texture, and flavor varies depending upon the timing of its harvest. Early-harvest or young ginger (harvested after six months) is tender and sweet, while older, more mature ginger (harvested between ten to twelve months) is more fibrous and spicy. Mature ginger is usually all that's available in American supermarkets, but young ginger can often be found in Asian markets. It's easily identified by its thin, papery skin, which can be left on, and pink-tinged tips. Look for ginger with skin (the thinner the better) that's smooth, unblemished, and almost translucent. When you break off the piece you want, the interior should be firm, crisp, and not overly fibrous (making it easier to slice). It should have a fresh, spicy fragrance.
Unless the ginger will be removed before serving (as when you infuse a liquid with a piece of it), fresh ginger should be peeled. Try using the edge of a metal spoon to scrape off the skin. It takes a bit more effort than a paring knife or a peeler, but it's less wasteful—and it lets you maneuver around the knobs and gnarls. Ginger can be sliced into planks or matchsticks, chopped, grated, puréed, and minced. Keep in mind that, like many spices, ginger's flavor fades as it cooks. So for more gingery oomph, add some or all of the ginger at the end of cooking.
Refrigerate peeled fresh ginger in a ziptop bag in the vegetable crisper drawer and it will keep for weeks. Dried and crystallized ginger may be kept at room temperature.