I love potatoes. Whenever I get visitors, I usually make a HUGE pot of mash for dinner since mashed potatoes are super versatile. But a recent visit turned into a no-show, and I had all of that mash left over. I wondered how long are mashed potatoes good for, and how could I ensure my mash stayed fresh as long as possible.
Fortunately, I have a super-talented aunt who cooks, bakes, and preserves food like crazy. She had some excellent guidance, so I won’t ever have to worry about potatoes spoiling again.
Basic mashed potatoes that have been cooked, mashed, and then refrigerated will last for 3-5 days (in the refrigerator), but when milk, butter, cream, etc. have been added to the mash, the window of freshness is shortened to as little as a day or two. Prolong the freshness of mashed potatoes by refrigerating them without adding anything to them.
Whenever mashed potatoes start to spoil, it makes a clear liquid, start to smell rancid, or (if left for way more than 5 days) will start to grow mold colonies.
Mash potatoes go bad really quickly at room temperature, which is why refrigeration or freezing is recommended.
How Long Will Mashed Potatoes Last in the Fridge?
Mashed potatoes that have nothing more than a bit of salt and pepper added will last for 3-5 days in the refrigerator.
However, if you add flavorings such as cream, milk, butter, or mayonnaise to your mashed potatoes, it will severely shorten the time you can keep them in the fridge.
The addition of dairy products will introduce bacterial cultures that start the molding process much sooner, causing the mash to spoil within a day or two.
How to Store Mashed Potatoes
My aunt had some excellent advice on how to store mashed potatoes in the fridge so they will keep them really well and optimize for the full five days so that they can stay fresh.
There are a few ways to keep mashed potatoes fresher for longer:
The best way to keep your mash ready to use, fresh, and moist is to keep it in a glass oven-proof dish with a sealable lid. This way, you keep the mash fresh in the fridge without it drying out, and you can simply pop it into the oven or microwave to heat through.
Freeze Mash Potato Balls
Another great way to keep mashed potatoes fresh for a lot longer is to freeze the mash in cling wrap. Simply scoop spoonfuls of mash onto cling wrap that’s placed over muffin pans, wrap in the film, bag in a zipper bag, then freeze.
Frozen mash will last as much as a year, and to warm up, simply place in the microwave for a few minutes until heated through, using the defrost setting, or place the unwrapped mash balls into the muffin pans and slow bake until warmed through.
Top Tip: If you want to keep mash fresh for longer, you wouldn’t add the cream, milk, or butter you would usually flavor it with as these make mash sour quickly.
Instead, freeze or refrigerate your unflavored mash, and once you’ve warmed the mash, add your flavorings, letting the butter and cream melt into the warm heated mash.
Vacuum Sealed Mash Potatoes
Another way to keep your mashed potatoes fresh for longer is to vacuum seal them with a mechanical vacuum sealer.
While this isn’t an option everyone has in their home, by removing the air from the vacuum bag, the mashed potatoes will last longer as bacteria and mold spores require air to grow.
Ensure you place the vacuum-sealed mashed potatoes in the fridge or freezer to further prolong their shelf life and keep them fresh for longer.
How Do You Know When Mashed Potatoes Go Bad?
There are a few signs that will tell you when your mash has spoiled and gone bad.
The smell of the Mash
When mash smells sour or yeasty when you open the lid, you know the mash is destined for the bin.
Color of the Mash
Should the mash become pale or darken into gray spots, you can bet mold is forming.
In time, the dry spots will become less glossy as mold spores form and bacteria start to digest the starchy potatoes.
Never consume potatoes or potato mash that has been in the fridge for a few days and that has a sour smell or odd coloring and texture. Food poisoning isn’t any fun.
The texture of the Mash
If the mash has spoiled, it will take on a spongy texture that can start to become like cardboard along the edges of the container. Fresh mash has a soft and fluffy texture.
Can You Eat Week-Old Mashed Potatoes?
If the mashed potatoes have been stored in the freezer and warmed through before serving, you can safely eat the potatoes a week after freezing (or even as much as a year later).
However, if your potatoes have been kept in the fridge for a week, the chances of mold having formed (even at a microscopic level) are high, making it a potential hazard for food poisoning.
What Happens When You Eat Bad Mashed Potatoes?
Not only will off-mash potatoes taste bad, but they can also lead to serious ill health and food poisoning.
If you eat moldy mashed potatoes and have a food allergy, you could go into anaphylactic shock, which can even lead to death.
My Last Foodie Thoughts
Mashed potatoes are and always will be a firm favorite in my family, and while it’s rare that we have leftovers, it does happen.
Thanks to my aunt, I now know just how to keep my mash fresh for the next day or even next year (in the freezer).
It’s all about keeping the mash cold, free of harmful bacteria, and limiting the oxygen that mold and bacteria need to grow.
What are your favorite tricks for keeping mashed potatoes fresh and ready to eat?