aiquestions© Ask AI Questions. All rights reserved 2026
How to Thicken Mashed Potatoes?
The gentlest fixes are to simmer the potatoes to evaporate excess liquid, or stir in a spoonful of instant potato flakes at a time until they firm up. Runny mash almost always means too much milk or butter went in, or a watery potato variety was used.
Updated Cooking & Recipes
Ways to thicken, best first
- Cook off the moisture. Put the pot back on low heat and stir gently for a few minutes; some of the liquid steams away and they firm up.
- Instant potato flakes. Sprinkle in a spoonful at a time, stirring, until the texture is right. This is the fastest, most flavor-neutral fix.
- More cooked potato. Rice or mash an extra plain potato and fold it in.
- Dairy for body. Stir in grated cheese, cream cheese, or a bit of butter — thickens and adds flavor.
- Starch slurry (last resort). A little cornstarch mixed with cold liquid, stirred in over heat. Use sparingly so they don't turn gummy.
The one thing not to do: don't try to fix runny mash by mashing harder. Overworking potatoes releases starch and turns them gluey and gummy — worse than thin. Warm the add-ins so you're not cooling the batch, and add liquid slowly next time.
Prevention: drain boiled potatoes well (even let them steam-dry a minute), and add warm milk/butter gradually.
You may also want How to Thicken Sauce? or How to Use Chopsticks?.
Neighbouring how-tos sit on other Cooking & Recipes questions. From the homepage you can ask a follow-up of your own — no account needed.
Researched content
Frequently Asked Questions
How do you fix runny mashed potatoes?
Simmer to cook off liquid, then stir in instant potato flakes a bit at a time, or fold in more cooked potato. Cheese or butter also thicken.
Can you use cornstarch to thicken mashed potatoes?
Yes, as a last resort — a small cornstarch slurry stirred in over heat. Use a little, or they can turn gummy.
Why did my mashed potatoes get gluey?
Over-mixing. Working potatoes too hard releases starch and makes them gummy, so don't try to thicken them by mashing more.