This Is Why Milk and Cookies Taste So Darn Good Together

Updated: Feb. 01, 2024

The reason you love milk and cookies so much? Delicious chemical reactions in your mouth you had no idea were happening.

Not even adults can deny this food fact: dunking cookies in milk is one of the best treats out there. Whether it’s with the perfect chocolate chip cookie that’s stored in the pantry or any other type of cookie Grandma would be proud of (like one made with white chocolate), the classic combo of milk and cookies is a recipe for happy taste buds and sweet nostalgia. In fact, eating milk and cookies is scientifically designed to taste good. Whether the first person to ever dip a cookie in milk knew that is another question.

Why do milk and cookies taste good together?

When you dunk a chocolate chip cookie, you change everything about it: the texture, the flavor, right down to the chemical composition. As Matthew Harting, a chemistry professor at American University, explained to Quartz, it all comes down to a group of chemical additives called emulsifiers.

Here’s how they work. There are some liquids that don’t naturally mix, the most common example being oil and water. An emulsion is when one liquid is chemically forced to disperse within the other. Instead of oil sitting on top of water, drops of oil are suspended throughout the water. The compounds that make this happen are called, you guessed it, emulsifiers. One end of this molecule likes oil and the other end likes water, so they allow two otherwise opposing liquids to happily coexist.

Both chocolate and milk contain emulsifiers. The ones in chocolate let fatty ingredients (oil and cocoa butter) mix with ingredients without fat (water and cocoa powder). They also keep the fat in milk from collecting at the top of your glass.

This delicious magic, aka science, is taken to the next level when chocolate chip cookies are dunked in milk because the emulsifiers from both substances interact on your tongue. Milk calms down the intense sweetness from the chocolate, according to Harting, and the emulsifiers “help to smooth out the chocolate as you’re eating it,” giving you the perfect creaminess-to-cookie flavor ratio. Otherwise, it could taste too gritty and crunchy. Inspired to bake some delicious cookies now?

Who came up with milk and cookies?

There’s no clear answer on who the first person was to dunk their cookies in milk (but whoever they are, we surely thank them). However, we can trace back the act of dunking itself. It’s believed to have started with the Romans, who dunked hard wafers in wine to soften them. Dunking is also believed to have been popular with sailors in the 1500s. Apparently, sailors were given very hard crackers to live on during long trips, which they dunked in coffee or brine to soften up.

We can also trace back a popular Christmas tradition involving milk and cookies, though not quite as far. Turns out, the tradition of leaving milk and cookies for St. Nick started back in the 1930s during the Great Depression. It was a way for parents to teach kids to show gratitude for gifts, even during hard times.

Now that you know the ins and outs of milk and cookies, get the scoop on who invented ice cream, one of the world’s oldest (and yummiest) desserts. Have you tried these San Nicolas cookies from the Philippines?


  • Quartz: “There’s a scientific reason why chocolate chip cookies and milk taste so good together”
  • GrouperSandwich: “Who Started Dipping Cookies in Milk?”
  • Irish Times: “Why do we dunk biscuits into tea?”