8 Mistakes to Avoid When Making Mashed Potatoes

updated Oct 19, 2023
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An aerial shot of creamy, buttery mashed potatoes with a chive garnish

No Thanksgiving spread is complete without a bowl of buttery, fluffy mashed potatoes. It’s a simple dish with few ingredients, but little mistakes can easily make this beloved side dish too gummy, too gluey, too mushy, too runny, or — the ever-classic mashed potato mistake — too lumpy.

We’ve rounded up eight of the biggest mashed potato mistakes you can make, so you can avoid them and ensure this major Thanksgiving player shines on the big day.

Credit: Joe Lingeman

1. Using the wrong type of potato.

Choosing the right potatoes for mashed potatoes is key. Avoid waxy varieties like Red Bliss and fingerling when making mashed potatoes. Because these varieties have a low starch content, they don’t break down or absorb dairy as well as other starchier varieties, and often result in a gluey or gummy texture when mashed.

Follow this tip: For fluffy mashed potatoes, use starchy potatoes, like Russets or Yukon Golds. Or better yet, use a combination of both.

While red potatoes aren’t the best choice for fluffy mashed potatoes, they can be used for a rustic thick-and-chunky mash.

Credit: Photo: Joe Lingeman - Food Styling: Maggie Ruggiero

2. Cutting the potatoes too small.

Cutting your potatoes makes the cook time go quicker, but it’s a delicate balance: You could actually cut them too small. When you cut the potatoes too small they will absorb too much water — and therefore not absorb as much of the dairy goodness you’ll be adding to them later on in the process. This can also lead to runny mashed potatoes (and nobody wants that).

Follow this tip: Try slicing your potatoes at least an inch and a half thick to be on the safe side — or better yet, just boil them whole!

Credit: Photo: Alex Lepe ; Food Stylist: Ben Weiner

3. Undercooking the potatoes.

Another classic mashed potato mistake is undercooking them. This leads to lumpy mashed potatoes, which are no one’s favorites (unless perhaps you are Ross Gellar).

Follow this tip: Check for potato doneness at 30 minutes. A sharp knife should be able to go through the potato easily. If you can’t stick a knife in it, try checking them again at 45 minutes (larger potatoes will take longer to cook). If you did accidentally undercook them, add in some milk and put them over low heat on the stovetop until they soften up a bit.

Credit: Photo: Alex Lepe ; Prop Stylist: Tom Hoerup

4. Not washing the potatoes.

Yes, you are going to peel them, but failing to wash the potatoes before you cook them is a big mistake. Unfortunately, pesticides and other chemicals may be present in the soil that the potatoes were growing in — and the last thing you want is for those to make their way into the creamy mashed potatoes you’re preparing.

Follow this tip: Grab a vegetable scrubber and wash the potato throughly under running water. Do this right before you prepare the potatoes, however. If you wash them too much in advance, they could spoil.

Credit: Joe Lingeman

5. Not salting the water.

Like pasta, potatoes absorb the water they’re cooked in. Leaving salt out means you’re starting off with bland potatoes.

Follow this tip: Begin the process of seasoning your mashed potatoes by adding salt to the water when cooking the potatoes. You won’t have to add as much salt later and, most importantly, you won’t find yourself with bland potatoes.

Credit: Melissa Ryan

6. Starting with hot water.

Adding potatoes to already-hot water increases the chances of uneven cooking. The outside of the potato will end up overcooked, while the inside will remain firm and underdone.

Follow this tip: For even cooking, place the potatoes in a large pot and add cold water to about an inch above the potatoes. Then place the pot on the stove and begin cooking.

Credit: Joe Lingeman

7. Adding cold butter and cream.

Butter and cream are critical for great mashed potatoes. When added straight from the fridge, not only do they cool everything down, but they also don’t get absorbed into the potatoes very well.

Follow this tip: Bring the butter and cream at least to room temperature, or gently heat them on the stovetop, before adding them to potatoes. Not only will the potatoes absorb the warm dairy much easier, but you also won’t have to work them as much to mix in the butter and cream. Less agitation means creamier mashed potatoes.

Credit: Faith Durand

8. Overworking the potatoes.

When potatoes are mashed, starch is released. The more you work the potatoes, the more starch gets released. When too much starch gets released, the potatoes become gummy, gluey, and unappetizing.

Overworking the potatoes can happen in a couple ways: either by simply handling them too much, or by using a food processor, blender, or similar tool, which mixes the potatoes too aggressively.

Follow this tip: Limit the amount you handle the potatoes. We also suggest using a ricer or food mill for fluffy, lump-free mashed potatoes.

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