The classic cocktail revival is in full swing these days, and it’s bringing vermouth back with it. For cocktail lovers, this is a very good thing.

Vermouth has been a staple bar ingredient since the cocktail era dawned in the late 19th century. In its heyday, lower-proof vermouth played a popular supporting role to stronger spirits like gin and whiskey. The classic martini (gin, dry vermouth, and bitters) and the Manhattan (whiskey, sweet vermouth, and bitters) are perfect examples.

Vermouth, with its delicate herbal flavors, takes the boozy edge off the gin and softens the whiskey in these cocktails, and does so without changing the drink’s structure too much (which can easily happen when you add juices or liqueurs). It dresses up the star spirit without overwhelming it. In short, it’s the perfect co-star.

Vermouth, defined

But what exactly is vermouth? It’s a wine that’s been macerated with a garden’s worth of botanicals, barks, and herbs (like marjoram, mace, orange peel, and wormwood, orwermutin German, from which vermouth takes its name). This aromatic wine is then fortified (which means extra alcohol is added to it) with neutral grape spirits. The resulting drink is balanced and complex, with flavors that can range from sweet to herbal to bitter.

There are two basic vermouth styles: dry and white, or French; and sweet and red, or Italian. The geographic reference indicates the style of the vermouth. And while both styles are made from white wines, sweet vermouth gets its dark red hue from the addition of caramel.

As a general rule (and every rule has its exceptions), sweet vermouths, which are more full-bodied, sweeter, and more bitter, hold their own against brawny, aged spirits like whiskey and brandy. Softer dry vermouths are more delicate and enhance the botanicals of white spirits like gin and white tequilas or rums.

The back story

In the late 18th century, in the former kingdom of Savoy (today’s northern Italy and parts of southern and eastern France), a few clever entrepreneurs began enhancing not-so-great local wines with herbs and spices and fortifying the wine with more alcohol to preserve it. Vermouth was born.

Commercial production began in 1786, when Antonio Benedetto Carpano, a distiller in Turin, Italy, started selling his version of vermouth. Most people enjoyed it chilled as an apéritif, a European tradition that continues to this day. In 1863, Martini & Rossi (today’s titan vermouth producer), came out with its own sweet vermouth, also in Turin.

Joseph Noilly developed his dry French-style vermouth in 1813 in Marseillan, France. Over the next 40 years, Joseph’s son, Louis, and his brother-in-law, Claudius Prat, got involved in what grew to become a global business, today’s Noilly Prat.

A co-star is reborn

Given vermouth’s rich, centuries-old European legacy and its major—albeit supporting—role in the early days of American cocktail history, it’s astounding how maligned and neglected, misused and misunderstood vermouth has been over the past few decades. You might say it started with Winston Churchill, who, as legend has it, considered it sufficient to just look towards a bottle of dry vermouth when making his gin martini (instead of actually adding vermouth to his glass). And then the 1990s hit, with that decade’s unfettered enthusiasm for bland vodka cocktails. Vermouth, with its seductive aromatics, was too strong a character. Dust gathered on bottles of Noilly Prat and Martini & Rossi everywhere.

But all that’s changing. The classic cocktail renaissance has moved from speakeasy-style bars in bigger cities to living rooms across the nation, thanks in no small part to the relentless popularity of television’sMad Men. People are mixing martinis and Manhattans with ice-jangling fervor and learning to appreciate vermouth’s complexity.

So for your next 5 o’clock cocktail, try mixing an iconicManhattan, in which vermouth’s sweetness tames rye whiskey’s bite. Or use dry vermouth to bring out the aromatics of your favorite gin in a crisp, coldmartini. Either is a fitting showcase for the cocktail world’s favorite co-star.

Vermouth Know-How

Buying
If you don’t mix martinis nightly and aren’t planning a party for this weekend, it’s best to buy the smallest bottle of vermouth you can find, since the wine will eventually oxidize after opening.

Storing
Keep open bottles in the refrigerator, and try to drink the vermouth within six weeks for optimal flavor and aroma.

Serving
Vermouth is a great mixer, but to best appreciate its distinctive flavor, drink it straight up, chilled, in a wine glass.