It all comes down to bacteria and moisture. When you mash potatoes, you're creating a perfect breeding ground for microorganisms to grow and thrive. And, trust me, you don't want to be eating a side of bacterial mashed potatoes with your dinner.
But don't worry, it's not all doom and gloom! If you store your mashed potatoes in an airtight container in the fridge, they can last for around 3 to 5 days. Just make sure to give them a good stir before reheating, or you might end up with a potato-flavored brick.
