According to Serious Eats, when your mashed potatoes end up with a pasty or a gluey consistency, it's due to an excess of starch.
If you want to keep your mashed potatoes from getting gummy the best way to do this is using a potato ricer. Otherwise, you can still make classic fluffy mashed potatoes without a ricer by using a Food Mill instead. Both will work best since it breaks down the cooked potatoes without excessive mashing.
A: The individual potato cells are susceptible to breaking down based on the amount of starch in the potato. Higher solids (starch) potatoes have larger cell size and tend to not break down as easily when over mixed versus a low solids potato (such as a red or yellow skinned variety) which has smaller potato cells.
Once mashed potatoes reach the glue stage, there's no going back. Your potatoes may taste fine, but the thick, gloppy texture could be more than your guests can stomach.
We already told you that the primary reason for rubbery mashed potatoes is overworking them. To avoid being too rough on your potatoes, use a hand mixer instead of an electric one. Electric mixers are powerful and oftentimes too harsh for certain foods, like potatoes. Dry the potatoes completely.
Don't over-mixing: I can't say it enough, DON'T mash the potatoes to much! As you mix potatoes it causes them to release their starch, which is necessary for creamy mashed potatoes, but too much mixing releases too much starch, and causes thick and gluey mashed potatoes.
Overcooked potatoes aren't always dry and hard, as it's possible to overboil a potato too. When you do so, more water is absorbed by the potato. Then, when you go to mash them, the water releases, resulting in that sad, soupy mess you may want to toss in a compost pile far, far away.
Next time, make sure you cook the potatoes fully by inserting a fork into them before taking them off the heat. If the fork slips in easily, they're done.
The best potatoes to use for mashed potatoes are Russet potatoes or Idaho potatoes because of their high starch content. Yukon gold potatoes are another good option, the texture of Yukon gold is a bit more buttery and not quite as starchy.
But the most essential suggestion, per Bon Appétit, is always to salt the water you are boiling your mashed potatoes in. It acts as pre-seasoning, and Bon Appétit recommends adding a full cup of kosher salt to the boiling water.
If you've been adding too much milk or butter, try cutting back to achieve the perfect consistency. Let your mashed potatoes sit for a few minutes before serving. As they cool, they will thicken up slightly.
If you've got lumps, don't panic. And also, don't keep mixing, because that could make your potatoes gummy as well. Instead, try putting the mashed potatoes through a potato ricer to try and break them up without overworking them.
Tip #3: Don't Overcook or Undercook the Potatoes
If you overcook them they disintegrate and your potatoes will be soupy. The specific cooking time depends on the size of your potato: a perfectly cooked piece of potato should give no resistance when cut with a knife, but shouldn't crumble into a million pieces.
Bring the water to a boil over high heat, then reduce heat to medium low. 5. Cover the pot and simmer until potatoes are tender — about 15 to 20 minutes. A knife tip inserted into a potato should meet no resistance; if the potato clings to the knife, the potatoes need to cook longer.
According to Southan, the reason for lumps in your mash is one of two things: either the type of potato you have selected, or the potatoes you're trying to mash are undercooked. Potatoes come in three main categories: waxy (kipfler, Dutch cream), floury (golden delight, sebago) and all purpose (coliban).
Tips for the Best Mashed Potatoes
Start cooking the potatoes in cold water: This ensures that the potatoes cook evenly. Otherwise, if you start with hot or boiling water, the outsides of the potatoes cook and soften while the middles are still hard and crunchy.
For most potato dishes it's important to add the potatoes to cold water and allow the water to come to a boil with the potatoes in the water. The potato starch can react as soon as it comes in contact with hot water, which will promote uneven cooking and mealy potatoes.
If you want them creamy, you need to get enough starch out of the cells to create some texture, but not so much that your potatoes become gluey (gluey = all the starch). If you want fluffy potatoes, you need to keep the starch to a minimum possible because it weighs them down.
Luxuriously smooth potatoes
If serving the creamiest, smoothest mashed potatoes is your dinnertime goal, consider whipping out the whisk to realize your vision. By using a whisk to make mashed potatoes, the work of transforming the cooked potatoes into a smooth side dish can be reduced.
You can also thicken your mashed potatoes by continuing to cook them on the stove with the lid off. Heat draws the excess moisture out of runny potatoes, leaving you with a denser finished product.
Boiling the potatoes makes their starch cells larger. While you want to break up these cells to create a nice consistency in your potatoes, you don't want to rupture these starch cells too much, as this makes the mashed potatoes gluey.
As already discussed, pastiness is caused by too much potato starch being worked into the mashed potatoes. The main way we combat this problem is by rinsing away starch, both before and after cooking potatoes for fluffy mashed potatoes. Rinsing off starch means that there is less of it that can end up in the dish.
If they're undercooked, you'll have pockets of crispy potato chunks-—a big no-no for classic fluffy mashed potatoes. If you overcook them they disintegrate and your potatoes will be soupy.