Russets (such as Idahos) are elliptical in shape and marked by a thick, rough brown skin with numerous eyes. Low in moisture and high in starch, they make excellent, fluffy mashed potatoes; because they tend to be a bit dry and mealy, they benefit from the addition of butter and milk or cream, which they absorb easily. To avoid gluey mashed potatoes, mix firmly but as briefly as possible.
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These large, oval potatoes have a golden skin and yellow flesh with a rich, buttery flavor and a moist, creamy texture. Their medium starch content makes them a good all-purpose potato suitable for both boiling and baking, although they tend to fall apart when cooked too long. They make exceptionally good mashed potatoes, French fries, and potato salad.
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The most familiar of red-skinned varieties, these are firm, round, moist, and waxy, with thin skins—a good choice for salads, for roasting with meats, or whenever you want your potatoes to hold their shape. They’re especially popular as new potatoes.
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Also called baby or creamer potatoes, these are any potatoes that are harvested young, before their sugars are fully converted to starch. Generally, the smaller they are, the better the taste. They’re sweeter and waxier than mature potatoes, with very thin skins that don’t need to be peeled. Since they’re firm and flavorful, they’re ideal for potato salads and roasting whole. They go soft quickly and should be eaten within 3 days.
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Firm and waxy, these small, slender, finger-shaped potatoes are 2 to 4 inches long. With varieties grown in red, purple, yellow, and gold, they make colorful potato salads or side dishes and are delicious roasted whole. They go soft quickly and should be eaten within 3 days.
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Look for small to medium-sized sweet potatoes, which are sweet and creamy. (The larger ones tend to be starchier.) The skin should be firm, smooth, and even-toned; the deeper the color of the potato, in general, the richer it is in the antioxidant beta-carotene. While orange sweet potatoes are sometimes labeled yams in the United States, true yams are starchy, white-fleshed tubers common to tropical countries—not your grandmother’s famed candied casserole. Keep sweet potatoes in a cool, dry place—think pantry, not refrigerator—for up to 2 weeks. Hang on to them longer and their high sugar content will cause them to spoil.