Among the 7,000 or so languages spoken across the globe, only one is universal: numbers. The way we communicate about whiskey is no different. Regardless of a whiskey drinker’s tasting experience or skill, numbers, or more specifically age, are the common denominator to loosely identify a whiskey’s quality.

More often than not, there’s a positive correlation between a bottle’s price and its age statement. The older the bottle, the more money you can expect to pay for it. And frequently, it’s the oldest bottles that tend to claim top spots at spirits competitions. But not always.

As the whiskey world expands, and new, unexpected countries introduce bottles to market, age statements are increasingly unreliable indicators of quality. Proving that time itself is relative, multiple distillers around the world argue it’s not so much about how long a whiskey ages, but where that process takes place.

The Angel’s Share: Whiskey Aging 101

Before we take a deep dive into the complexities of age statements, a quick primer on the whiskey aging process: The longer a spirit spends in a barrel, the greater the concentration of flavor compounds it draws from the aging vessel. As the liquid takes on these complex compounds, the volume of spirit inside the barrel constantly decreases due to evaporation. (This lost spirit is known in the industry as the “angel’s share.”)

At a certain point, oak character can overpower the flavors imparted by the base ingredients and the fermentation process, knocking the overall profile out of balance. This combination of factors explains why it’s highly uncommon to find whiskeys aged for longer than a few decades. It is also the reason why an 18-year-old single malt Scotch retails for more than a 12-year-old expression from the same producer. Those six extra years in barrel add complexity — something that’s usually attributed to quality — but because the volume of whisk(e)y the producer can ultimately sell is lower, it has to charge more for each bottle.

It’s a fairly straightforward equation. But this simple concept and the value of age statements become much more complex when examining the conditions in which barrels and their contents age.

Age vs. Maturity

North Carolina-based Raj Sabharwal is an award-winning spirits importer. Among his portfolio at Glass Revolution Imports is Amrut, an equally prestigious, pioneering Indian single malt producer. The distillery shot to fame in 2010 when noted whisky connoisseur Jim Murray named Amrut Fusion, a single malt made with Scottish and Indian barley, the world’s third-best whisky. (He scored it 97 points out of 100, for those interested in the numbers.)

While it’s typically bottled around six years old, Amrut Fusion does not contain an age statement on its labels. “One year in India — at least at Amrut — is like three or four years in Scotland,” Sabharwal says. “So, originally, when we started importing Amrut, we felt that if there was an age statement on it, it would deter people.”

Located in Bangalore in southern India, Amrut’s distillery lies some 3,000 feet above sea level, and around 200 miles from either coast. At this altitude, temperature highs range from 75 degrees Fahrenheit in winter to 120 degrees in summer, Sabharwal explains. Because of its inland location, the humidity at the distillery remains relatively low year-round, swinging between 45 percent in the winter and 75 percent in summer. In Scotland, by contrast, average annual lows and highs range from 36 to 66 degrees Fahrenheit, while humidity hovers between 70 and 90 percent.

The difference in conditions has a big impact on aging. “In Scotland, the angel’s share evaporation rate is 1 to 2 percent per year, whereas in Bangalore it’s 10 to 15 percent,” Sabharwal says.

Additionally, the actual science behind the angel’s share is not only a measurement of evaporation, but of contact and molecular exchange between spirit and cask. In hotter, drier conditions, barrels expand and contract more rapidly, and the spirit gains the barrel’s flavor compounds in tandem. In other words, it matures at a faster pace.

For this reason, Sabharwal says, age statements are flawed. While a single malt Scotch may just be hitting its stride after 12 years in barrel, in other parts of the world, it may have already passed its peak maturity by this point. “I prefer to talk about maturity versus age,” Sabharwal says.

David Vitale, founder of Melbourne, Australia’s Starward Whisky, echoes Sabharwal’s sentiment. While the numbers printed front and center on whiskey bottles are a literal statement of age, he says, maturity “is contextual.”

When prevailing winds hit from the Outback region north of Melbourne, it’s like “opening up an oven door,” Vitale says. Meanwhile, blasts of humid, cooling breezes arrive from the Antarctic. It’s not uncommon for both influences to hit on the same day. Because of this, Starward’s whiskies experience huge diurnal temperature swings throughout the year. These extreme swings account for an evaporation rate of around 5 percent per year, and significantly increase barrel expansion and contraction. “We’ve got some of the hardest working barrels in the world,” Vitale says.

Vessel Variations and Flavor

In order to navigate such volatile conditions, barrel selection is paramount. Starward ages both its single malt (Nova) and double grain (Two-Fold) whiskies in former wine barrels, sourced from nearby producers. In the distillery’s early days, Vitale says, the expectation was that the better the wine that came out of the barrel, the more suitable that vessel would be for aging whisky. Over time, however, he learned that’s not the case. Certain barrels — specifically those that previously held bolder, more extracted wines — are more susceptible to overpowering the spirit. Melbourne’s relatively extreme aging conditions only amplify the phenomenon.

“As much as this is a whisky aged in wine barrels, this is a whisky first,” Vitale says. “Aussie wines are known for being quite brash, and it would have been easy for us to be the Aussie Shiraz of whisky. But we wanted to be more nuanced and layered than that.”

Barrel conditioning versus aging is also a hot topic in arid Oaxaca, Mexico, where master distiller Douglas French makes Sierra Norte’s Mexican whiskeys. Much like Vitale at Starward, French has learned how to optimize the unique aging conditions at his distillery (hot and dry) through years of experience.

Sierra Norte’s whiskeys are made using 85 percent Oaxacan heritage corn and 15 percent malted barley. While other whiskey distilleries focus on cask finishing and different age statements, Sierra Norte offers multiple expressions using distinct strains of corn, such as yellow, white, or black. “Discovering that the different colors made different flavors was mind-blowing,” French says. “I want those natural, raw materials to come through.”

Rather than time, the most important factor in aging Sierra Norte’s whiskeys is the char level of the barrels they rest in, French says. Like Starward, Sierra Norte ages its whiskeys in former wine barrels; but being based in Mexico means French has much less control over the casks he receives. Some have a much deeper char than others, which causes the whiskey to mature more rapidly. Depending on the barrel, Sierra Norte’s whiskeys can reach maturity anywhere between six and 18 months.

French defines the point of maturity for his whiskeys as the moment in which they turn from a “silver” to “brown” spirit, both in terms of flavor and appearance. Overall, it’s the spirit’s flavor that matters, not its evaporation rate (6 to 10 percent per year, French says).

In recent years, producers in far-flung locations from Sweden to Taiwan to Argentina have each released high-point-scoring, critically acclaimed bottles, all without an age statement in sight. Even in Scotland, notable producers including The Macallan, Ardbeg, and Glenmorangie have added non-age-statement bottles to their lineups, none of which are mere lower-cost, budget alternatives. This wild variation of aging conditions reflects the complexity of whiskey maturation — and calls the universal significance of age statements into serious question.

Of course, time will continue to play an integral role in whiskey production. But when it comes to quality, numbers really only tell half the story.