Potato characteristics are grouped by variety, by skin color, by shape and by use. Two important qualities of each variety determine the best way to prepare it.
High Starch / Low Moisture Potatoes are also described as having high solids. Washington russet varieties average 20-30 percent solids and are best for baking, mashing, frying or pureeing. The cooked potato is described as dry, fluffy and mealy. This is because the large starch granules absorb the internal moisture as they cook, then expand and burst, creating the mealy texture that results in fluffy baked potatoes, light mashed and pureed potatoes and crisp-outside-fluffy-inside French fries.
Russet Burbanks are preferred for French frying because their low sugar content keeps them from discoloring as they fry and because starch on the surface of the cut potatoes expands with the heat and dries the surface as it absorbs water from the potato. The result is a crisp skin with a fluffy interior. Fries made from high moisture varieties (reds) go limp because the internal moisture content turns to steam as they cook. Early season Russet Norkotahs, though light-frying, have lower solids than Burbanks, so have to be watched for oil absorption during frying. Norkotahs increase in sugar content during storage, so those coming out of storage in the spring and summer may darken when fried.