There are over 4000 varieties of potato in the world today and they are part of the nightshade family . What makes them so special… Are they really that different? Yes!
Potatoes are classified by their starch content and divided into 2 main types: Waxy (or New) and Mealy( or Mature/or Starchy).
Waxy - Waxy potatoes are thin skinned, have a high moisture content, high sugar content, and a low starch content. Most of the varieties of waxy potatoes are small and round though some are long and elongated. The flesh color of waxy potatoes is white, yellow, or blue, and the skin is white, red, yellow, or blue. Waxy potatoes are not optimal for deep fat frying. Great boiled whole and consumed unpeeled. Red potatoes and fingerling potatoes are examples of waxy potatoes.
Pro-Tip when working with Waxy/New Potatoes: As these potatoes have more moisture and less starch, they will absorb less cooking water/mayonnaise/vinaigrette making them more resistant to breaking when tossed in a salad.
Mealy - Mealy Potatoes are thick skinned, have a high starch content, low moisture and a low sugar content. Generally long shaped, they have rougher skin than a waxy potato and is often peeled. As the mealy potato is larger, drier and mealy when cooked, it is great for deep fat frying, baking and mashing. Russets and Idahos are examples of mealy potatoes. Yukon Gold potatoes are mealy potatoes, but due to their thinner golden flesh and golden flesh, make a great all purpose potato that if most often consumed unpeeled.
Pro-Tip when working with Mealy/Mature Potatoes: As these potatoes are drier, starchier, and mealier than waxy potatoes, they become lighter textured when baked. Mealy potatoes are the best for frying because of the low moisture content, they won’t “pop” as much.
Sweet Potatoes (Yams) – the common myth is that sweet potatoes are orange or white potatoes. This is not true. Though the flesh is similar, this starchy sweet tasting tuber is actually part of the Morning Glory family, not nightshades. Avoid sweet potatoes with soft ends as this is an indication of the beginning of breakdown and spoilage. And yes, ALL YAMS ARE sweet potatoes!
Storage and Quality Characteristics:
Always store potatoes in a dry, dark area when temperatures do not exceed 65-70 degrees. Exposure to light will cause the potato to develop green areas. These areas contain Solanine (a natural deterrent produced when potatoes are uncovered so hungry insects and animals will not eat them) and will be very bitter and are poisonous in large quantities. Any green areas should always be cut off and discarded before cooking. Never refrigerate potatoes as the cool temperature will convert some of the potato starch to sugar making the potato sweet. This process can be reversed if you leave a refrigerated potato at a temperature of 50 degrees for two weeks. Potatoes should have dry, tight skins regardless of if they are mealy or waxy.