Order a sazerac in New Orleans and a well-meaning local will likely tell you how the city’s official cocktail is also the world’s first. It’s not true, of course – the word “cocktail”, originally referring to a mixture of liquor, sugar, water and bitters, was used long before the sazerac’s 19th-century creation. But don’t tell New Orleans residents that, for whom the drink is a serious point of pride: virtually any bartender in New Orleans can mix the drink without even glancing at a recipe.

“Even before we knew about cocktail culture, we were making sazeracs at friends’ house parties,” said Kirk Estopinal, owner of New Orleans cocktail bar Bellocq.

Typically made with rye whiskey, a couple dashes of Peychaud’s bitters, an absinthe or herbsaint rinse, simple syrup or a muddled sugar cube and a lemon twist, the sazerac is an amalgamation of flavours just as New Orleans is an amalgamation of cultures, like French, Creole and Cajun. And just as the city has changed over time, so has the sazerac.

The drink originally got its name from a brand of French cognac named Sazerac-de-Forge et Fils. According to legend, sometime in the mid-19th Century, an establishment called the Sazerac House (until then known as the Merchant’s Coffee Exchange) mixed the cognac with sugar and Peychaud’s bitters – the purported cure-all of local pharmacist Antoine Amédée Peychaud – and the sazerac cocktail was born.

But in the late 1800s, a phylloxera epidemic devastated the French grapes used to make cognac, making the spirit incredibly hard to find. Around the same time, it’s said that locals began to prefer rye whisky, replacing cognac as the sazerac’s base ingredient. Absinthe’s popularity also had begun to skyrocket, so a rinse of the herbal, anis-flavoured spirit found its way into the glass.

In 1949, the Sazerac House moved into the Roosevelt Hotel and became the Sazerac Bar. After Hurricane Katrina forced it to close in 2005, the hotel reopened in 2009, completely renovated with a long walnut bar, elegant tile floor and white coat-wearing wait staff, nodding to the former opulence of old New Orleans. Today, it remains one of the city’s most iconic places to sample the classic drink.

While there, I ordered the contemporary sazerac as well as a cognac interpretation, which more closely resembled the drink’s original incarnation. With the contemporary sazerac, the rye packed a wallop of spice and heat, intensifying the mix of flavours. The cognac version had a similar complexity, but resulted in a much mellower drink. In both versions, the sweetness from the sugar mixed wonderfully with the bite of the bitters.

While the Sazerac Bar represents the city’s fancier side, Jean Lafitte’s Old Absinthe House is the epitome of a city nicknamed The Big Easy. Located in the historic French Quarter – a neighbourhood with no closing time, no open container laws and to-go cups at many bars – the bar has been serving drinks almost without stop since 1807, including during Prohibition. Even during Hurricane Katrina in 2005, the Old Absinthe House only closed for a matter of hours, slinging drinks until it ran out of booze.

It’s the type of place where its common to find a dishevelled street musician arguing with a buttoned-up lawyer about the songs playing over the jukebox – not an establishment where you’d expect a sazerac to be served alongside other local classics, such as the Ramos Gin Fizz, a notoriously laborious gin-based cocktail mixed with simple syrup, lime juice, egg white, heavy cream, orange flower water and club soda, shaken for eternity.

The spicy rye sazerac I sampled at Jean Lafitte’s Old Absinthe House was made a little less carefully than the cocktails at Sazerac Bar or Belloq. Of course, this is also a bar that still has a reverse peep hole once used by pirates to pick out the house prostitutes– and a secret window once used to spot prohibition officers. Part of the experience’s enjoyment stems from being able to sit in bar where vintage football helmets hang from the ceiling and business cards paper the walls, savouring a drink that would be considered fancy in any other city.

Even though the bar has an extensive absinthe list ­– and the previously illicit liquor has experienced a revival since becoming legal again in the US in 2007 – the 25-year-veteran behind the bar rinsed my sazerac glass with herbsaint, a local pastis that remains the more popular choice for sazeracs since replacing absinthe when it was outlawed more than 100 years ago.

In many ways, that makes sense. In cities all over the US, bars are designed to look like pre-prohibition establishments and faux-speakeasies change their cocktails weekly to keep up with the newest trends. But in New Orleans, suspenders and handlebar moustaches never went out of style; live Dixieland jazz never stopped blasting from Creole townhouses; and many of the bars never left pre-prohibition behind. New Orleans isn’t as concerned with reviving what’s gone as it is with preserving what never left.