Whether you enjoy it on the rocks or in a sidecar, celebrate this National Cognac Day with a long pour and these seven facts about the fine French brandy.

1. ALL COGNAC IS MADE IN COGNAC, FRANCE.

Much like how Scotch must be made in Scotland and Champagne in the Champagne region of France, cognac must be produced in a specific region to be labeled as such (otherwise, it's a different type of brandy). It must be grown in one of the six zones, or crus, in the Cognac region of France. Each cru—Grande Champagne, Petite Champagne, Borderies, Fins Bois, Bons Bois, Bois Ordinaires (or Bois à Terroir)—has a distinctive soil quality due to the presence of clay, rockiness, or chalky soil, which changes the flavors of the cognac grapes.

2. THE COGNAC-MAKING PROCESS IS SPECIFIC AND COMPLEX.

In accordance with Appellation d’Origine Contrôlée, a French certification agency, the grapes must come from the Cognac region, the wine has to be distilled twice in copper pot stills, the eau de vie—technically, any distilled spirit, but here a colorless brandy—must be aged in French oak barrels for at least two years, and at least two eaux de vie must be blended together.

“Unlike grain spirits, which can be produced all year round, cognac can only be made during a specific time of year,” Tomas Delos Reyes, mixology ambassador for Moet Hennessy, tells Mental Floss. The grapes are harvested from September through October and immediately turned into wine. Once that process is completed, the next stage is distillation, which happens from November through March. The resulting eau de vie is then stored in oak barrels to mature for a minimum of two years.

“Once it's ready, then you have the final step where all the magic and patience comes full circle—in the blending,” Reyes says. “The art of blending is where our generations of Master Blenders let their craft truly shine in the consistency of each cognac.”

3. THERE ARE THREE CLASSIFICATIONS OF COGNAC.

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As you peruse the shelves at the liquor store, you may notice that each cognac label is marked with a few letters. These let you know how long the cognac has been aged. The youngest cognac is the Very Special (V.S.), which is aged at least two years in oak barrels. Reserves that are aged at least four years receive the Very Superior Old Pale (V.S.O.P.) label. The oldest blend is known as Extra Old (X.O.), and it is aged at least six years.

However, due to the large inventory of cognac aged for more than a decade, a new classification category—Napoleon—will become standard by April 2018, Eater reports. Napoleon will indicate that the cognac has been aged for a minimum of six years, while X.O will shift to designate cognacs aged a minimum of 10 years.

4. COGNAC WAS ONCE THE GO-TO SPIRIT.

Throughout the 1800s, cognac was the bartender’s base spirit of choice, says Tyler Phillips, senior brand manager of D’USSÉ. Cocktails that use whiskey today, including the Sazerac (which was actually named for a popular type of cognac, Sazerac de Forge et Fils Cognac) or the mint julep, were created with cognac in mind. In fact, according to 19th century mixology books, what we commonly call a mint julep today was once known as a whiskey julep. “While cognac is typically known today as a sipping spirit, it actually has deeper roots in mixology,” Phillips says. According to Phillips, its complex flavor blends well with fruits and juices, making it perfect for cocktail-making.

5. PEAK COGNAC IS CALLED "RANCIO."

The Portuguese term is given to a blend of cognac when it reaches its optimal flavor and aroma levels, but its definition is difficult to nail down—even for experts. "It's a special taste," Pascal Dagnaud, the master distiller at Ragnaud-Sabourin, told the Washington Post in 2009. "It's close to caramel, but a little bitter. It tastes a little like a bitter nut. It's a special taste."

There are four stages of rancio, which correspond to how long the cognac has been aged. Stage four, the oldest, is for cognac's aged 50 to 60 years.

6. THE SIDECAR'S ORIGINS ARE DISPUTED.

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One of the best-known cognac cocktails is the sidecar (traditionally made with cognac, orange liqueur, and lemon juice). The exact origins of the drink are in dispute, but the most common story is that the cocktail was created during the early 1900s in Paris. Reps for Moet Hennessy and D’USSÉ claim it was created at Harry’s New York Bar by an anonymous army captain who liked to ride in a motorcycle sidecar. Rémy Martin, however, believes it was created by a mixologist at the Bar Hemingway at Hôtel Ritz.

But James Beard winning mixologist Dale DeGroff doubts this story. He argues that the sidecar was just an updated version of the New Orleans classic the Brandy Crusta. And as for the name? He says, “The word sidecar means something totally different in the world of the cocktail: If the bartender misses his mark on ingredient quantities so when he strains the drink into the serving glass there’s a bit left over in the shaker, he pours that little extra into a shot glass on the side—that little glass is called a sidecar.”

7. THE PRICIEST COGNAC WAS PURCHASED IN CHINA.

You can find good cognac at every budget level—including very, very high (Rémy Martin Louis XIII, for example, retails for over $3000). However, that price tag pales in comparison to the 1858 Cuvée Léonie. According to Guinness World Records, Cuvée Léonie is the most expensive bottle of cognac ever was sold at auction. In 2011, it was purchased at an auction in Shanghai for 1,000,000 CNY—or $156,740.