If you look at the nutritional composition of various potatoes—a hell of a way to spend a Friday night—you’ll find that so-called “starchy” potatoes are indeed especially high in starch. But their mashability comes as much from what’s not in them: simple sugars like fructose and galactose as well as fibers like pectin.
Simple sugars attract and trap water in the potato, which makes for a relatively wet mass of starch that doesn’t easily absorb butter and cream. Meanwhile, fiber acts as the potato’s connective tissue, and since fiber doesn’t dissolve during cooking, a high-fiber potato is kind of like a gristly steak. Both require a lot of chewing and pounding to break down, and lengthy mashing is what turns an innocent bowl of cooked spuds into a dense, pasty mess of tangled starch molecules.
Compared to “starchy” potatoes, “waxy” potatoes are relatively high in these simple sugars and fibers. So save them for potato salad.
- Who: Yukon Golds · Mashed Potatoes · Greens With Salt-Cured Egg
