All potatoes contain starch, sugar, water and a few nutrients. In fact, one of the most nutritious parts of a potato is its skin, so you may want to keep it in your mash. The wide variety of potatoes makes the different tastes, colours and textures of mash, so choosing which type you use alters the overall result significantly.
High Starch Russets and Idaho Potatoes
Many people consider the potato varieties with the most starch the best for mashing. The Russet and the Idaho are both excellent examples. They make creamy, richly-coloured mashed potatoes. According to Reluctant Gourmet, the Yukon Gold also falls into this category, although it had less starch than the Russet. Starch cooks and swells at about 65.6 degrees Celsius, so starchy potatoes like the Russet make fluffier mashes.
Low Starch Reds and Rounded Whites
Lower-starch potatoes can also be used for mashing, but they give a waxier, fuller flavour that divides opinion. Examples include the Red Rose and White Rose potatoes. The mash tastes heavier and less fluffy, but has a rich, appealing flavour that goes well with red meats and sausages. Low-starch varieties take longer to mash into a smooth texture, but it can be done, and the result avoids the "starchy" taste some people dislike in high-starch potatoes.
A large, starchy potato with a purply skin and white flesh, the Caribe is ideal for mashing, as described by Cook's Thesaurus. It is suited to the technique of mashing because it is so soft and mushy when cooked and does not retain its shape. Caribes also have high yields and grow in a range of environments, so are popular for home growing and can produce up to 1.81kg. per hill, according to Backyard Gardener. Caribe mash goes well with roast beef meals and fried chicken. The green skin and shoots of the caribe plant are not suitable for eating and can be toxic to humans.
Sweet Potato Mash
An alternative to savoury mashed recipes is the sweet potato or the addition of some sweet potato to ordinary savoury mash. If you add an extra ingredient like sweet potato, or even a vegetable like a parsnip, it is referred to as a "mashing partner" because it complements the basic recipe. There are many different types of sweet potato such as the Puerto Rican, the Covington, the 414 Purple and the Murasaki, as described by the North Carolina Sweet Potato Commission. They are found in an appealing range of colours, from dark red to bright orange, and can be mashed like any savoury variety. As with ordinary potatoes, their textures and flavours differ from creamy to starchy, fluffy to moist.