The Nature of Things·Chef Secrets

Perfect mashed potatoes: Leave the skins on, don't use a masher and use 'a comical amount of butter'

Culinary scientist Ali Bouzari spent four years perfecting and replicating this recipe

Culinary scientist Ali Bouzari spent four years perfecting and replicating this recipe

The secret to perfect mashed potatoes? Leave the skins on when you boil them; use a tamis, sieve or a food mill to mash them; add a comical amount of butter. (CBC/Chef Secrets: The Science of Cooking)

Torn between becoming a chef or a biochemist, Ali Bouzari realized he could be both by studying culinary science. In graduate school, Bouzari spent four years perfecting and replicating a method for making the smoothest, creamiest mashed potatoes. 

“Basically, I wanted to map out: how does the tissue of a potato shift and change during cooking and how does that give you awesome — or not so awesome — mashed potatoes?” he says.

Yes, he has a PhD in mashed potatoes. And yes, he’s willing to share his recipe.  

Culinary scientist Ali Bouzari spent four years perfecting mashed potatoes for his PhD. "I wanted to learn: what is it that makes potatoes creamy? What is creaminess? How does that change with the amount of water you cook potatoes in? The amount of fat? The amount of salt, does salt matter?" (CBC/Chef Secrets: The Science of Cooking)

In Chef Secrets: The Science of Cooking, a documentary from The Nature of Things, Bouzari demonstrates the science behind the transition from hard, raw potato to soft, creamy goodness.

Ali Bouzari’s Mashed Yukon Gold Potatoes 

This rich and creamy recipe is more of a “framework” for Bouzari’s mashed potatoes. Feel free to experiment with ingredient quantities until you get your perfect result. (In Chef Secrets, he calls this "a comical amount of butter.")

This recipe makes enough for seven to 10 people.


  • 2 kg Yukon Gold potatoes, skin on
  • 200 g milk, cream or similar creamy liquid
  • 20 g kosher salt, plus more to taste
  • 500 g unsalted butter, at room temperature (or up to 2 kg, if you’re feeling hedonistic)


In a large pot, boil the potatoes whole — with their skins on — until fork-tender.

In a separate pot, combine the milk and salt. Place it over the lowest heat setting to warm through.

Once the potatoes are cool enough to handle but still warm, pass them through a mesh tamis, potato ricer or food mill to disintegrate the potato tissue and separate the flesh from the skins. The potatoes should go directly into the warm milk pot.

Say goodbye to the hand masher for smooth, creamy mashed potatoes. A tamis or food mill is the key to Ali Bouzari's perfect mashed potatoes. (CBC/Chef Secrets: The Science of Cooking)

Stir the butter into the potato mixture (I like to use a flexible spatula), mixing over low heat until fully incorporated. (I typically add the butter a small handful at a time, mix until fully incorporated, then add more.) 

Add additional salt to taste, if desired. Cover the potatoes to keep them warm until serving.

Ali Bouzari is a culinary scientist at a research lab that works with some of the world’s best restaurants. He's the author of Ingredient: Unveiling the Essential Elements of Food.

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