How do you make butter at home?

When you buy butter in the store, it usually comes in neatly wrapped sticks and bricks. But what is butter? How is it made by hand? And what does butter look like when you make it at home?

In this Bon Appétit video, flavor scientist Dr. Arielle Johnson explains that “butter is what happens when we take the milk fat out of milk.” She demonstrates how you can make cultured butter at home using heavy cream, buttermilk, a dash of optional salt, and some physics and chemistry.

And she explains the science along the way, including the importance of lactic acid bacteria, fermentation, a molecule called diacetyl, protein, carotene molecules, and more. It may sound complex, but the steps are simple… just a bit messy without some practice.

For variations with written instructions, visit Epicurious and NYT Cooking.

Then see how French artisanal butter is made: Chef Ludo Lefebvre visits the Bordier Butter Factory.

Bonus: Loaf of Bread, Container of Milk, Stick of Butter.