3 to 4 days
In shallow covered containers (USDA FoodKeeper, FSIS)
1 to 2 months
Best quality; FoodKeeper allows mashed potatoes up to 10 to 12 (USDA FoodKeeper)
2 hours
1 hour above 90°F (USDA FSIS)
The short version: get mashed potatoes into the fridge within 2 hours, in shallow covered containers. Then eat them within 3 to 4 days, the time the USDA gives leftover cooked potatoes. For longer, freeze them. Finally, reheat leftovers to 165°F and stir well.
Storage times here come from the USDA's FoodKeeper data and the USDA Food Safety and Inspection Service's Leftovers and Food Safety and Turkey Basics: Handling Cooked Dinners pages.
On this page
What to do before you store mashed potatoes
Mashed potatoes keep best when they cool quickly, because the USDA Food Safety and Inspection Service says bacteria grow rapidly between 40°F and 140°F. So deal with the leftovers soon after the meal, rather than at the end of the evening.
Into shallow containers soon after the meal.
Firstly, watch the 2-hour limit. FSIS says to throw away perishable food left at room temperature longer than that, or 1 hour above 90°F.
Secondly, split a big pot into smaller portions. FSIS explains that large amounts of food cool slowly, so it tells you to refrigerate potatoes in shallow containers.
Then cover each container. Wrapping leftovers keeps bacteria out, holds in moisture and stops them picking up other smells, as FSIS notes.
Finally, decide what to freeze while the mash is fresh. The raw spuds have their own guide, how to store potatoes, and leftover turkey follows the same 3 to 4 day rule.
How to store mashed potatoes
To store mashed potatoes, cool them fast, cover them and keep them cold. After that, the fridge gives you a few days, while the freezer gives you months.
How long can you keep mashed potatoes in the fridge?
You can keep mashed potatoes, or mash, 3 to 4 days in the fridge, because the USDA's FoodKeeper data gives leftover cooked potatoes that long. Similarly, FSIS gives all leftovers 3 to 4 days. So mash from Thursday dinner should be eaten or frozen by Monday.
Covered, in shallow containers.
Can you put hot mashed potatoes in the fridge?
Yes. The USDA Food Safety and Inspection Service says hot food can go straight into the fridge, as long as you divide it into smaller containers first.
So spread the mash into shallow dishes rather than chilling the whole pot. In fact, FSIS also suggests an ice or cold-water bath to speed up cooling. The rest of the holiday table has its own guides: leftover turkey, ham, and pumpkin, apple and pecan pie. For another side, see how to store corn on the cob.
Can mashed potatoes sit out overnight?
No. Mashed potatoes left out overnight should be thrown away, because the USDA Food Safety and Inspection Service limits perishable food to 2 hours at room temperature. The food left out overnight guide covers the rest of the table.
How should you wrap mashed potatoes?
Seal mashed potatoes in airtight containers, or press plastic wrap onto the surface before adding a lid. That way, as FSIS explains, you keep bacteria out and hold in moisture. Then label each container with the day.
How do you reheat mashed potatoes safely?
Reheat mashed potatoes to 165°F, as the USDA Food Safety and Inspection Service advises for all leftovers. Cover the dish, since FSIS says covering retains moisture and helps food heat through. In the microwave, also stir and rotate it, because microwaves leave cold spots.
Can you freeze mashed potatoes?
Yes. The USDA's FoodKeeper data notes that its 10 to 12 month freezer time for potatoes applies to cooked and mashed potatoes. However, its general entry for leftover cooked potatoes gives only 1 to 2 months. So aim for the shorter time for best quality, and use the longer one as an outer limit.
How do you freeze mashed potatoes?
Freeze mashed potatoes once they are cold, in portions you will use at one meal. Then flatten them in freezer bags or pack them into shallow containers, since FSIS says airtight wrapping keeps out air. Finally, label each one with the date.
Flattened in bags, in single-meal portions.
How do you thaw frozen mashed potatoes?
Thaw them in the fridge, in cold water or in the microwave, the three safe ways FSIS lists. Alternatively, reheat them straight from frozen, which FSIS says is safe but takes longer. Then stir well as they heat.
Can you refreeze mashed potatoes?
Yes, in two cases. FSIS says leftovers thawed in the fridge can be refrozen. It also says leftovers reheated to 165°F can be frozen again. However, mash thawed in cold water should be reheated before it goes back in.
How to tell if mashed potatoes have gone bad
Mashed potatoes can be unsafe before they look bad, since the USDA Food Safety and Inspection Service says the bacteria behind food poisoning do not generally change how food looks or smells. So count the days first. Then check the signs below.
Verdict: eat it
Fresh mashed potatoes
Creamy, pale and smooth, with a mild buttery smell. In other words, this is mash that went into the fridge within 2 hours and is inside its 3 to 4 days. So reheat it to 165°F and serve it.
Verdict: eat it or freeze it today
Mashed potatoes on day 3 or 4
Mash that looks normal but has a slightly dry, firm top after a few days covered in the fridge. Even so, it is at the end of the window FoodKeeper gives. So eat it today, or move it to the freezer now.
Verdict: throw it out
Mashed potatoes left out more than 2 hours
A bowl that stayed on the table or stove through the evening, even if it looks perfect. FSIS says to discard perishable food left out more than 2 hours. So throw it out, because reheating does not fix it.
Verdict: throw it out
Sour or slimy mashed potatoes
A sour or off smell, a watery or slimy layer, or a grey tinge. These are signs of spoilage, so stop there. In fact, Clemson Cooperative Extension says to discard stored food with an off odor, so do not taste it.
Verdict: throw it out
Moldy mashed potatoes
Fuzzy spots of white, green, pink or black on the surface. The USDA Food Safety and Inspection Service says to discard moldy cooked casseroles and similar dishes, because moist foods can be contaminated below the surface. So throw out the whole container.
Do mashed potatoes with milk and butter keep less?
No source we opened gives them a shorter time. The USDA's FoodKeeper data gives leftover cooked potatoes 3 to 4 days, and FSIS gives cooked dishes the same. So follow 3 to 4 days whatever went into the pot, and freeze the rest by then.
How long mashed potatoes keep, by type
The clock depends on where the mash is. So here is each case.
Substitute
Works best in
What changes
On the table
2 hours
1 hour above 90°F (USDA FSIS).
In the fridge
3 to 4 days
Shallow, covered containers (USDA).
In the freezer
1 to 2 months
Best quality; FoodKeeper also gives up to 10 to 12.
Thawed in the fridge
3 to 4 days
Or refreeze it (USDA FSIS).
Mistakes people make with leftover mashed potatoes
These are the ways leftover mash goes wrong most often, and each one is easy to fix.
Chilling the whole pot. Split it into shallow containers so it cools quickly.
Leaving the bowl out all evening. Two hours, then into the fridge.
Waiting for it to cool on the counter. Hot food can go straight into the fridge.
Keeping it a week. Eat it within 3 to 4 days, or freeze it.
Warming it only until it is warm. Reheat it to 165°F, stirring as you go.
Scraping off a moldy spot. Moist foods can be contaminated below the surface, so bin it.
Forgetting the freezer. Mash freezes well, so freeze spare portions early.
Sources
FoodKeeper App, Food Safety and Inspection Service, U.S. Department of Agriculture, whose published FoodKeeper data lists leftovers without meat, such as cooked potatoes, at 3 to 4 days refrigerated and 1 to 2 months frozen, and potatoes at 10 to 12 months frozen, a time it says applies to cooked and mashed potatoes.
Leftovers and Food Safety, Food Safety and Inspection Service, U.S. Department of Agriculture, on the 40°F to 140°F danger zone, the 2-hour and 1-hour rules, cooling in shallow containers or an ice bath, putting hot food straight into the fridge, wrapping, thawing, reheating to 165°F and refreezing.
Turkey Basics: Handling Cooked Dinners, Food Safety and Inspection Service, U.S. Department of Agriculture, on refrigerating potatoes in shallow containers and cooked dishes at 3 to 4 days.
Refrigeration and Food Safety, Food Safety and Inspection Service, U.S. Department of Agriculture, on pathogenic bacteria not generally affecting the taste, smell or appearance of food.
Molds on Food: Are They Dangerous?, Food Safety and Inspection Service, U.S. Department of Agriculture, on discarding moldy cooked casseroles and other moist foods.
Safety of Stored Foods, Clemson Cooperative Extension Home & Garden Information Center fact sheet HGIC 3520, revised April 2020, on discarding stored food with an off odor.
Storage times and safety advice on this page come from the sources above. Food safety depends on conditions I cannot see, so read the Disclaimer, and if in doubt, throw it out.
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