Food - Drink
Why You Shouldn't Use Cold Milk For Mashed Potatoes
The key to perfect mashed potatoes is in the mixing, and it's imperative that the spuds are not overworked. Irrespective of how you prefer your mashed potatoes, handling the potatoes releases starch and a higher quantity of starch makes the potatoes stickier, resulting in a glue-like texture that's hard to swallow.
Approximately 85% of the potato's solid matter is starch, with the rest made up of water and it's hard to avoid. Serious Eats recommends washing the potatoes before and after boiling to remove excess starch and to also keep handling to a minimum, while also suggesting using a ricer or a food mill to get a smooth mash.
Southern Living notes it takes a lot of effort for cold milk to absorb into a hot potato, which means more mixing. Warming the milk — and bringing any other dairy product to room temperature — cuts down on blending so the starch doesn't have time to form a gluey goo.