Watery leftover mashed potatoes usually happen because the potatoes absorbed too much water during boiling (overcooking or small cuts), excess liquid was added (milk/broth), or moisture separated out during chilling (starch retrogradation), causing the excess water to release, notes The Kitchn and Reddit users and Instagram users. To fix it, you can cook out moisture, add thickeners like instant potatoes, or use a ricer for smoother results next time.
The best way to thicken runny mashed potatoes is to use a thickening agent, such as corn starch, potato starch, or tapioca starch. Add any of these one tablespoon as a time and stir into your mashed potatoes until you reach your desired consistency.
If you cut your potatoes beforehand into small pieces and let them overcook, it is possible, that they adsorb too much liquid. Or if you didn't really drain them. And when you put the mashed potatoes into the fridge the excess water was free, making the mash potatoes watery.
If they're too watery, your potatoes are probably waterlogged. Boiled too long. Put them back in the pot, cook out some moisture. Mash.
How To Fix Runny Mashed Potatoes. Whether you added to much liquid or over-mashed your potatoes, if you wind up with a soupy mess of gloop instead of fluffy, whipped spuds, we have a solution for you: Just add instant mashed potatoes (aka potato flakes). These little flakes are essentially dehydrated potatoes.
The most common mistake when making mashed potatoes is overworking them with a blender, food processor, or mixer, which releases too much starch and turns them gluey or pasty instead of fluffy. Other frequent errors include using the wrong potatoes, not salting the cooking water, starting potatoes in boiling water, and adding cold butter/milk.
Starch is released when potatoes are mashed, smashed, or whipped, and, if too much starch is released, the potatoes are gummy and unappealing. Limit the amount of time you handle the potatoes, mashing or whipping only until the potatoes reach the desired consistency.
Runny potatoes can happen for a few different reasons. Too much liquid: This is the most common reason. In the mashing process you may have added too much milk or broth. Boiled too long: Boiling your potatoes for too long can make them water-logged, which (you guessed it) can contribute to runny mashed potatoes.
Over time, the rot widens inside the tuber, gradually liquefying it. The bacteria can spread throughout the storage area in the ooze leaching from decaying tubers.
It's all in how you mix: Too much force, like from a food processor, breaks the potato's starch granules and releases extra starch, creating that gummy texture no one wants. Hand-mashing keeps those granules intact, giving you creamy, cloud-like potatoes every time.
Try draining the cooked water off in a sieve or colander and then placing back on the stove to cook out some of the extra moisture, just a couple of minutes. Mash with a masher (or a ricer which makes great non lumpy spuds). Always add melted butter or the liquid when it is warm and do this a little at a time.
Add a Thickening Agent
This is the most common way to thicken mashed potatoes. You can use what you have on hand: Flour, cornstarch, or powdered milk are all solid options that are probably already in your pantry. Potato flour and potato starch would work as well.
The best mashed potatoes are made with starchy potatoes (like Russets or Yukon Golds), boiled until tender, seasoned heavily in salty water, and mashed with warm butter and cream or milk using a ricer or food mill for fluffiness, avoiding overmixing to prevent gumminess, and incorporating flavor boosters like roasted garlic or herbs. Key secrets include using a ricer for airy texture, warming liquids, and salting the cooking water generously.
When Chef Gordon Ramsay learned to perfect pomme purée in Paris, the mix was about 60 percent potato and 40 percent butter and cream. If you use dense, waxy potatoes and cook them following Gordon's modernized method, you can up the potato flavor and only use about 10 percent fat.
There are different schools of thought as to whether the butter should be melted or room temperature, but most agree the dairy products shouldn't be cold. Cold milk will cause the starch to seize up.
The Mistake: Overworking the Potatoes with a Food Processor, Blender or Mixer. Too much — or too vigorous — mashing will produce gluey potatoes. Your best tool is an old-fashioned masher, fork, ricer or food mill.
Salt the water before boiling, taste as you mash and don't be shy when reaching for the butter dish. “Butter is the cornerstone of that rich, velvety flavor,” says Gaydos, and he's right. Many chefs also fold in heavy cream, sour cream or even cream cheese for extra tang and richness.
The mayo gives the mashed potatoes a smooth, velvety texture, and tons of extra flavor. Add in some milk and butter and you've got a winning mashed potato recipe in my book. Now let's talk about that mayo for a sec… Y'all know Duke's is my mayo of choice.
Mistake #3: You're over/undercooking the potatoes Overcooked potatoes are mealy, and therefore not delicious. Undercooked potatoes are too chunky to whip into a smooth mash. You'll know your potatoes are perfectly done when a sharp paring knife passes through the potatoes without any resistance.
Mistake #4: You're using a food processor, blender, immersion blender, or hand mixer THIS IS IMPORTANT: Potatoes are filled with starch, and starch does NOT like to be overworked. When you handle/mix/beat/whip starch too much, it breaks down and tightens up.
Use starchy potatoes like russet or Yukon gold for fluffy mashed potatoes. Avoid over-mashing to prevent a gluey texture; use a potato ricer or hand masher. To fix runny mashed potatoes, try oven drying, adding more potatoes, mixing in potato flakes, or stirring in cornstarch.
When mashed potatoes chill, their starches firm up nicely, and when they are reheated gently, they relax back into a mash with an even silkier texture. Made in advance or not, the way you prepare your spuds is absolutely crucial — never use a food processor, blender, or hand mixer.
Fix them: Scoop the watery mashed potatoes into a pan and stir constantly over low heat to evaporate the excess liquid. If the potatoes are really watery, you can add either cornstarch or instant mashed potatoes a half teaspoon at a time to help the spuds thicken to your preferred consistency.