How to Thicken Mashed Potatoes: 9 Easy Methods

It’s no secret that mashed potatoes are a staple side dish for traditional dinners, holiday celebrations and even comfort food. But what happens when you add too much liquid and you’re racing the clock to get dinner on the table? Don’t feel bad; it happens to the best of us!

Try one of the seven methods below to learn how to thicken mashed potatoes like a pro and save your side dish. No one will even think you ran into any obstacles along the way.

1. Mix in potato flakes

If you have dehydrated potatoes in your pantry, you can use them if you’re unsure how to thicken up mashed potatoes. Stir in 1 tablespoon of the instant potato flakes until your mixture reaches the desired consistency. While they can slightly alter the taste, they work wonders if you’re in a pinch.

2. Add starch

Flour and cornstarch can thicken mashed potatoes quickly. These are the best options in terms of pure thickening power if you want to achieve a denser consistency.

Mix ½ teaspoon of one of these thickening agents with cold water to create a slurry before stirring it into the hot potatoes. This will help prevent clumping. Gradually add the slurry until you reach the desired thickness. Start small. You can always add more if needed. 

While you can use any thickening agent, we recommend cornstarch, which is gluten-free and doesn’t alter the taste. Regular flour is discouraged because it needs to be cooked thoroughly to eliminate the raw flavor and kill any harmful bacteria. Adding it directly can cause your mashed potatoes to become gummy.

3. Add powdered dairy

Powdered milk or powdered buttermilk can be excellent options for thickening mashed potatoes. Simply sprinkle a tablespoon or two into your hot potatoes and stir well. The powders absorb excess liquid and boost the creamy dairy flavor. 

Avoid adding too much at once to prevent gluey mashed potatoes. Gradually incorporate the powder, tasting as you go. If the mash becomes too thick, stir in a splash of milk or cream to loosen it up.

4. Add cream cheese or sour cream

If you’re wondering how to fix gluey mashed potatoes, a few tablespoons of softened cream cheese or sour cream should do the trick. These dairy options will melt smoothly into your potatoes, increasing density and adding a tangy flavor. 

For best results, let the cheese or sour cream come to room temperature before mixing. Incorporate gradually into the mash, mixing thoroughly after each addition for a creamy, flavorful side dish.

5. Add hard cheeses

Stirring in a handful of shredded hard cheese such as Parmesan, sharp white cheddar or Gruyère adds both bulk and fat, helping the potatoes hold their shape better. The cheese melts into the mash, creating a richer, more cohesive texture. 

For best results, use freshly grated cheese to prevent clumping and fold the cheese in while the potatoes are still hot so it melts evenly. Keep in mind, the cheese also introduces saltiness, so adjust the seasoning accordingly.

6. Add more potatoes

Did you save some potatoes for a rainy day? Cook the last batch of potatoes you have lying around to add to your runny mashed potatoes. Combine both batches of mashed potatoes in a saucepan on the stovetop. The heat will help the potatoes blend together to create perfectly thick mashed potatoes.

7. Try using the oven

Just like the stovetop, an oven set at 300 degrees Fahrenheit is another option to thicken mashed potatoes quickly. Add your mashed potatoes to a baking dish and cook them for five to 10 minutes, depending on how long it takes for the moisture to dry up. Make sure to leave your baking dish uncovered so the moisture isn’t trapped.

8. Try stovetop reduction

If you’re unsure how to thicken mashed potatoes, you can try the simple method of turning up the heat on the stovetop. Slightly increase the temperature on your stove and cook your potatoes with the lid off — this helps draw out more moisture from runny mashed potatoes. Make sure to stir every minute or so, but don’t overwork the potatoes, which can cause them to become sticky or gummy.

Increasing the temperature helps the liquid evaporate and compounds the mixture. This method also works if you need to thicken sauces.

9. Zap it in the microwave

A quick way to add more thickness to watery mashed potatoes is the microwave. Place your potatoes in a microwave-safe container and cook them on high for one minute. Stir and check the thickness of the potatoes. If they still have moisture, cook them for an additional minute. Continue this process until your potatoes have a smooth consistency that isn’t runny.

How to get a smooth potato consistency

While there’s no right or wrong consistency, as some folks enjoy mashed potatoes with lumps, you can follow these steps to make smooth and creamy mashed potatoes every time.

Choose the right potatoes

The first step is to choose starchy potatoes (low in moisture with creamy flesh), which transform into a soft, fluffy consistency when cooked. Yukon gold potatoes or russet potatoes work well. Red-skinned and fingerling potatoes aren’t good options because they don’t absorb much liquid and can lead to a gummy texture.

Start with cold water

Make sure you aren’t adding your potatoes to boiling or hot water because the outside will cook faster, causing an uneven level of doneness. Instead, add your potatoes to a pot of cold water and then slowly increase the heat. Once your water starts to boil, turn down the temperature to simmer — this helps the potatoes keep their shape and maintain the perfect consistency.

Don’t overmash your potatoes

It’s easy to overwork your potatoes during the mashing process. You can use a mixer, blender, food processor or any other electric mixing tool if you’re in a pinch. Or you can use a potato masher and manually mix them. 

Mastering the technique will require practice and patience. In the meantime, try to reduce your speed and avoid vigorous mixing. Overworked potatoes release excess starch, causing gooey mashed potatoes.

Use room temperature add-ins

If you’re adding any liquids to your smooth and creamy mashed potatoes, make sure they’re warm or room temperature. When you mix in cold ingredients, they can alter the texture and temperature of the potatoes. Make sure to add the ingredients gradually so you don’t end up with runny mashed potatoes.

Mashed potato recipes

Looking to spice up your mashed potatoes? Check out these mashed potato recipes to find your next favorite method.

• Creamy mashed potatoes 

• Mashed potato pancakes

• Creamy garlic mashed potatoes

• Loaded mashed potatoes with bacon

• Hamburger gravy with mashed potatoes

• Shepherd’s pie

Through thick and thin — get your potatoes delivered

Now that you know how to thicken mashed potatoes, why complicate the shopping process with last-minute stops at the grocery store? Whether you need a thickening agent like cornstarch or an extra batch of potatoes to mix into your runny mashed potatoes, Instacart has you covered. Place an order today and receive everything you need right to your door.

Need more food ideas? Check out these comfort food dinner recipes to soothe your soul. Looking to spice up your holiday dinner? Try these non-traditional Thanksgiving dinner ideas.

How to thicken mashed potatoes FAQ

Still wondering how to make mashed potatoes thicker and reach the desired consistency? Check out the FAQs below for more tips.

How do you fix consistency in mashed potatoes?

To fix the consistency of mashed potatoes, start by heating them gently on the stove to allow excess moisture to evaporate. You can also add thickening agents like instant potato flakes or cornstarch gradually until you reach the desired texture. If they’re too thick, a splash of milk or cream can help loosen them up.

Will sour cream thicken mashed potatoes?

Yes, sour cream can help thicken mashed potatoes while adding a rich, tangy flavor. When mixed in, it contributes both creaminess and thickness, making it a great option for achieving the perfect consistency. Just be mindful of the amount; start with a few tablespoons and adjust to taste.

Why do my mashed potatoes taste watery?

Watery mashed potatoes often result from using too much liquid during preparation or overcooking the potatoes, which causes them to lose their starch. To prevent this, it’s best to add liquids gradually and stop once the desired consistency is reached.

Why are my mashed potatoes gummy?

Gummy mashed potatoes result from overworking or mashing the potatoes too vigorously. Using a hand masher gently and avoiding electric mixers helps prevent this. Also, using starchy potatoes and not overcooking them can keep the texture light and fluffy.