Can You Swap Milk With Sour Cream In Homemade Mashed Potatoes?

Mashed potatoes are one of those quintessential side dishes that show up on the table during holidays, and at your favorite steakhouse or chicken joint. They're soft and creamy and adaptable depending on the flavor profile you're hoping to enjoy. You can serve them with butter, or gravy... you can even add garlic to them for a more decadent taste. Mashed potatoes can also be made with different types of potatoes, although Good Housekeeping recommends high starch varieties like Russets and Yukon Golds for the fluffiest mashed potatoes.

Unlike their cousin, the baked potato, which is often topped with a pad of butter or a dollop of sour cream, mashed potatoes get all of their creaminess mixed in so that you get some of that luscious texture with every bite. Mashed potatoes are generally made with potatoes, milk, butter, salt, and pepper so you might be wondering if you can substitute other dairy products like sour cream in place of the milk. Let's explore!

For many people the appeal of a fully loaded baked potato is the sharp tanginess of the sour cream, yet sour cream is not traditionally added when making mashed potatoes. While there is a case to be made for adding a bit of sour cream to your mashed potato recipes, you definitely don't want to swap the milk for sour cream, and the big reason is texture. 

According to The Kitchn, sour cream is much denser than milk and so you'd end up with very stiff potatoes if sour cream replaces the milk in your recipe. Because milk is a liquid, it helps take the potatoes' stiffer mass and soften it, giving them their signature texture. My Recipes also notes that potatoes are highly absorbent, so they will absorb whatever you add to them. The liquid nature of milk makes mashed potatoes creamy without making them watery. Too much sour cream on the other hand has the opposite problem. It would turn them to paste.

Sour cream is much richer than milk and it could make your potatoes too rich (per The Kitchn). Adding a touch of sour cream to your potato recipe can add a bit of richness and some zip without taking away from the texture you may be desiring when making mashed potatoes. 

If you're looking to add a richness to your mashed potatoes without sacrificing texture, My Recipes suggests boiling your potatoes in milk and then adding some of that milk mixture later when you mash your potatoes. With this method, your potatoes leave a bit of their starch in the milk that you end up using for mashing, so you get the keep their flavor. Plus the potatoes will already begin to absorb the milk as they're cooking which gives them that added richness without your having to use too much butter or sour cream. Next time you're looking to make mashed potatoes at home, feel free to get the sour cream out of the fridge, just don't forget the milk.