I wish I was a sufficiently sophisticated coffee drinker to wave away milk when it’s offered, with a curt, I-take-it-straight wave the way I saw the real coffee men (and women) I interviewed do while researching my book The Joy of Coffee.

But after doing my best to imitate them, I admitted the truth: I like milk in my espresso, and usually in my brewed coffee too, even if real coffee men say that’s the way of the weakling.

I know all the arguments against it. Just as a dark roast can muffle discordant notes in slightly defective beans, milk can smooth out dull or imbalanced blends and roasts. Dark roasts and foamed milk, now inseparable companions and synonymous with European sophistication thanks to Starbucks, can also be co-conspirators that hide the flaws in coffee — and in fact the countries where coffee-and-milk drinks first took hold are ones that bought less than the best coffee.

Coffee men like Jerry Baldwin, one of the three founders of Starbucks and later the owner of Peet’s, want customers to appreciate the full range of flavors in the coffee they’ve trekked to Kenya or up a Guatemalan mountain to procure: the singing acidity that in the coffee world is a sign of sparkle and life, and that can burn off in the roaster; the funk and mouth-filling body of an Indonesian bean. Listening to customers order latte after cappuccino after latte one day, he said in exasperation, “Sometimes I want to tell everyone once a week that it’s the cow’s day off.”

But milk can deeply and broadly enhance the flavor of coffee, acting as olive oil in vegetables and in cream sauce can: as a flavor amplifier that attenuates the subtlest notes in a blend.

And there’s no way around the comforting, stomach-settling effect warm milk has. Milk softens and elongates a short shot, and provides a pillowy cushion to set off what can be the angular, intensive flavors of a well-pulled espresso.

So there’s your rationale. Here’s a list of some of the ways other cultures combine milk and coffee. I’ll start briefly with the two that have been most abused though Starbucks made their names universal — cappuccinos and lattes. Briefly, cappuccinos (probably named for the white hoods of brown-robed Capuchin monks) is a 1:1:1 ratio of espresso, steamed milk, and foamed milk. It sounds stingy to an American, and is. But the creaminess of the warm milk blends with the cap of foam above, and the syrupy espresso finds its way up the sip to be the last and lasting flavor. A properly made cappuccino is both lush and restrained.

A latte, well, hardly exists in Italy outside of the nursery. It’s one part espresso to three or parts steamed milk and barely any foam. It’s mostly hot milk with a little flavoring and buries the espresso. It’s what enrages a purist like Baldwin. And we won’t even mention caramel, peppermint, and any of the other crimes committed in its names. Pretend you’ve never heard of it, and practice ordering short cappuccinos for an approximation of the way Italians would serve them.

Before cappuccinos and lattes there was cafe au lait — both in this country and in France, which of course gave the drink its name. There’s a reason: cafe au lait is a home drink that requires no special equipment and barely a stove. It’s just brewed coffee, usually through a filter but also made in the stovetop Neapolitan flip-drip pots the French have traditionally used (coffee boils in the bottom of a double pot with ground coffee in a filter between the halves; when the water is pot you flip over the pot and wait for the water to drip through). While the coffee brews you scald milk in a pot, pour it into a deep bowl, then drizzle brewed coffee over it. It’s almost like soup, and ideal for dipping a split baguette slathered with raspberry jam — the French tartine. The proportions are a third to a half coffee to milk; as with most coffee drinks in most cultures, the ratio depends on the maker, who generally announces that she or he knows exactly the right degree of milk to coffee. A cafe creme is the same drink but possibly with espresso, generally with less milk, and possibly with foamed milk, a relative newcomer to France. (The proportions make it similar to the Spanish cafe con leche.)

Milk took hold early in France, which originally sold coffee chiefly from its colony of Martinique, placing tariffs on coffee from other countries. The coffee of Martinique, as with much of the Caribbean, where the climate is too hot to grow subtly flavored beans, is generally acidic and low in flavor; it benefits from both a darkish roast to mute some of the sharper notes and a milk bath.

The Nordic countries and Germany imported the highest-quality beans from the time they began drinking coffee. They roast light, which best brings out the full range of flavors in the Indonesian (from the historic Dutch colony), Central American, and African beans they buy, and add milk much as the Americans who took many of their coffee-consuming habits from Scandinavian and German immigrants do: with whole milk, generally unheated, added to taste. Filter coffee, or steeped campfire-style coffee, the Nordic styles, are thin-bodied and dilute enough to be sipped barely consciously and for a long time, which helps explain why Scandinavia has long topped the rest of the world in per-capita coffee consumption, and by a long shot. (But only helps. The main working theory for the fairly stupendous figures is the long northern nights and cold climate.)

The hotter the climate, the shorter the drink.

The current milk-coffee drink in fashion — the one purists like Baldwin can countenance — is the Spanish cortado, a shot of espresso or small amount of strong brewed coffee “cut” with an equal amount of hot milk.

Generally served in a small shot glass or, at the street markets in Miami, where Cuban immigrants first popularized it in this country, in tiny plastic cups the size of hospital pill containers, the cortado offers an ideal dark-roast jolt. The thick-textured hot milk seems to give extra weight to the drink, which feels much heavier than the espresso drink it most resembles, the Italian macchiato — a shot of espresso with a teaspoon or so of hot milk and a cap of foam that “stains” it. Another reason for the weight betrays the cortado’s hot-climate origins: it is typically made with condensed milk, which needs no refrigeration and has a nearly infinite life, and is powerfully sweet and rich. (Condensed milk is out of fashion, except as the main ingredient of dulce de leche. Try it with coffee, in the 1:1 ratio the Vietnamese do, dripping a single cup of filter coffee over a waiting cup of condensed milk. You may regret how much you like it — as with the dangerously irresistible Viennese kaffee mit schlag, coffee with whipped cream.)

The culture that has best fused Nordic, North American, and Latino is Australia, which is the most recent inventor of espresso-foamed milk drinks and has given the world a new blend: the “flat white,” which the Australian food historian Michael Symons insists is a rare collaboration between Australia and New Zealand that began to take form in the late 1980s, after Italian espresso and customs had become established and artisan roasters and baristas were starting to put their own stamp on drinks. (A “long black” is an espresso elongated with hot water, similar to the americano.)

A flat white is a double espresso with a small amount of steamed milk. How the milk is steamed makes all the difference: it’s “wet” vs “dry” foam, with tiny bubbles that just aerate it while giving it a velvety, thick texture. It’s much easier to make bubble-bath foam that looks dramatic but dissipates right away; micro-bubble, wet foam takes much more skill, and blends much more stably with espresso, to create an interwoven texture all of the same weight. The Italians, inventors of espresso, would not like to hear that someone has bettered a drink they gave the world. Try a flat white carefully made by an expat, and you might find yourself ready to offend the pride of an entire country.