"If you want the most velvety, plush mashed potatoes, you’re going to need a ricer. To understand why, it’s important to know what makes potatoes gummy in the first place: overworking the starches in cooked potatoes. Much like gluten in cake batter, it’s vital not to overmix—rather, overmash—your taters. … 'A ricer is something that can’t be replicated or replaced. It mashes potatoes into a texture that's uniquely silky and entirely free of lumps. As someone who prefers smooth mashed potatoes, I really do stand behind it.' "
"Yes it's true, and yes, it gives good results if what you're looking for is a very smooth, creamy mash. If you want a fluffy mash with bites of potato in it, you'll get better results using a traditional potato masher. … What actually comes out the business end [of a ricer] is shattered potato; the crystallized starch is broken up into fine, uniform pieces that, when mixed with fat, result in a smooth and creamy mash that's not very gluey like overworked mash can be."