What are the best potatoes for mashing into those golden, buttery piles of steamy starch — the ones that, when made properly, are equal parts rich and fluffy?
Yukon Gold potatoes are the best for mashed potatoes. Yukon Gold potatoes have the densest and most uniform flesh of the potato varieties.
When cooked, they aren’t grainy, watery, or mushy, which all happen to be qualities that ruin mashed potatoes instantly.
And as an added bonus, Yukon Golds already have an inherent buttery flavor to them. So you’re starting with more butter flavor, without any actual butter.
Idaho potatoes (a.k.a. russets), on the other hand, are less ideal for mashing. They don’t love being cooked in water, because their crazy-high starchiness absorbs a ton of it (which is why they work in our mashed baked-potatoes recipe, where they get cooked in the oven, but not in other boil-then-mash techniques).
When russets cook, the starch molecules get blown out, which can yield an unpleasantly gluey texture if they’re mashed and whipped too aggressively.