Have you ever boiled a potato and helplessly watched it fall apart? Or wanted rice to clump together for the sake of eating it with chopsticks and then had to chase individual grains around your plate? Odds are, you picked the wrong type of starch for your dish.
In the case of rice, short-grain and long-grain varieties both contain two kinds of starch, but it’s the ratio of the starches that make the rice react to heat differently. The type of starch in long-grain doesn’t reach its popping point until about 200 degrees F; the short-grain starch will burst (become sticky) at 165 degrees F. That means that long-grained is more suitable for dishes where you want the grains to remain separate: pilafs, rice salads, as simple side dishes tossed with a bit of oil and spices. (Examples: jasmine, basmati.) Short-grain is better for sushi, rice pudding, paella and stir frys. (Examples: Spanish, pearl.) Arborio rice occupies a peculiar middle position and is used for making risotto, an Italian dish wherein the grains are slowly simmered with liquid (trickling it in as you go) and served with Parmesan cheese. The final product is a rice that’s starchy enough to thicken its own sauce but is still crunchy inside.
Potatoes also come in three basic varieties: high-starch, medium-starch, and low-starch. The trade-off for high starch is low moisture, which means that the end result is a fluffy, dry potato, one that’s easy to mash and stuff. (Their high absorption rate also means, however, that they’ll fall apart when you boil them, so don’t use these for potato salads and other situations requiring a solid, still-shaped-like-a-potato cooked potato.) The opposite high-moisture, low-starch potatoes hold their form well and are wonderful used in baked gratins and soups and stews calling for potato chunks. Medium-starch potatoes are the all-purpose variety and are especially suited for roasting. It might be easier to remember that high-starch potatoes are sometimes called “baking potatoes” since they’re better prepared that way, and low-starch varieties are known as “boiling potatoes” since they’re stovetop-friendly.
Some common examples: Baking potatoes: Russets (Idaho)–brown, thick, flavorful skins Boiling potatoes: Fingerlings–long, slender, with thin skins; these taste like butter all on their own
Yukon Golds–roundish and pale brown, thin-skinned and with a yellow flesh
Redskins–round and pink, with thin skins and a slightly peppery flavor All-purpose potatoes: White potatoes–round and/or Russet-shaped potatoes, medium-thick skins
Purple potatoes–you can’t beat these for sheer exotic appeal, especially in pureés!