Question: how long can you keep cooked mashed potatoes in the refrigerator?
Answer: Cooler temperatures, such as those afforded by a pantry or root cellar, allow them to keep longer than at room temperature. Once cooked, potatoes last up to 4 days in the refrigerator and 1 year in the freezer, though the quality of cooked mashed potatoes suffers with freezing (4, 5).