Bacon and eggs.
Steak and red wine.
Apple pie and ice cream.

Some foods just go together.

In fact, there’s a method, called food pairing, to determine which foods and beverages will complement each other well. And researchers actually publish detailed studies on the subject.

What about coffee and milk? There are scientific reasons why they go so well together, and rigorous research has been done on the subject. You probably don’t need any research to answer the question, though. Coffee and milk are an iconic combination because they taste so darn good together.

You’re not the only one who understands that. It’s why restaurants automatically put a pitcher of milk (or cream) on the table when they serve your coffee, and upscale coffee drinks made with coffee and milk have become enormously popular.

How popular? Well, lattes made from espresso and milk are now the most-ordered coffees in America, with more than 67 million lattes served during the last calendar year they measured such things. That’s right, people order lattes more often than they order a regular coffee with milk and sugar.

Let’s figure out the reasons behind those amazing numbers.

The first recorded evidence of someone adding milk to coffee dates back to 1660, when a Dutch ambassador to China adapted the local tradition of adding milk to tea. Later in the 15th century, an Austrian coffee owner started serving coffee with milk because his customers didn’t like the bitter taste of the strong Turkish brew he offered.

An enduring, worldwide tradition was born.

But what makes the pairing such a great match for coffee drinkers?

The simple answer is that milk counteracts the natural bitterness in coffee that’s produced by its acidity. The more detailed answer is that the proteins in milk (specifically casein and whey proteins) combine with coffee’s antioxidant polyphenols to create the taste we know and love as “coffee and milk.” (If the science interests you, Nestlé has also done research showing that the beneficial effects of polyphenols aren’t affected when coffee is mixed with milk.)

Before we move on, there’s one more reason to consider adding milk to your coffee or coffee drink: it provides additional health benefits, and we’re not just talking about milk’s vitamins, nutrients and contribution to bone health. Drinking very hot coffee can obviously cause throat burns, and those burns appear to increase the danger of suffering throat cancer. Using milk to cool down your coffee isn’t just common sense, it’s medical sense, too.

Pouring milk into a cup of coffee is easy. Making a latte is harder. But it’s worth the extra effort.

The full name for a latte is caffe latte (often incorrectly written as “café latte”). The term is derived from the Italian “caffè e latte,” meaning – not surprisingly – “coffee and milk.” But “coffee and milk” doesn’t begin to do justice to a well-made latte.

To begin with, a latte isn’t made with what Americans think of as coffee – it’s made with espresso. If the drink is made with brewed coffee it’s not technically a latte. It’s “café au lait,” the French term for “coffee with milk”. (Want to get even more confused? In Northern Europe, for some reason, they call a latte “café au lait.” But we digress.)

Surprisingly, the latte seems to be an American invention; it wasn’t even served in European coffee shops until the middle of the 20th century. These days, it’s almost as ubiquitous as the cappuccino.

Espresso and milk are the key ingredients of a latte. They’re usually combined in a ratio of 1/3 espresso and 2/3 steamed milk, with a small layer of textured milk “microfoam” on top. Naturally, you want to use high-quality espresso, and whole milk will create the best froth.

But using the right technique for making a delicious latte is just as important as having the right liquids to make it with.

1. Start with freshly-brewed espresso at the bottom of your mug or latte glass. Latte is usually made with one shot of espresso, but double the milk if you’re using a double shot of espresso.
2. Next, put milk into a milk jug so it’s about half full (no, it doesn’t literally have to be a jug). You’ll be using the steam wand on your espresso machine to foam the milk, but be sure to purge the steam wand first. 
3. Start with the wand an inch below the surface of the milk, and slowly lower it toward the bottom of the jug. That will create a whirlpool of milk, with a nice layer of milk foam at the top. Steam until the milk reaches 140°F.
4. Swirl the jug to remove air bubbles, then pour the milk into the espresso. This is where baristas truly earn their stripes; they start pouring from up high, then slowly lower the milk jug and pour from a steeper angle, in order to ensure a perfect, thin layer of microfoam. (The best baristas create what’s called “latte art,” patterns or designs in the foamed milk.)
5. Yummm!

Of course, the drink will taste almost as good if you don’t use professional techniques. But if you’re going to do something, it pays to do it right. Right?

When a recipe becomes a classic, it doesn’t take long for people to play around with variations on the recipe. And several variations of this already-perfect espresso coffee drink are popular enough to be served at coffee houses around the world.