The Magic Barrel: The Art & Science of Aging Spirits
This handy guide breaks down the most important and least understood elements of aged spirits.
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A few weeks ago, the Macallan released a Scotch that had been aged for 52 years. A bottle costs $53,500.
Q: How much is a liquor-year worth?
If you answered $1028.85, congratulations! Your math skills are on point. Unfortunately, you’ve failed on liquor aging. Because the correct answer is: null and unknown.
Don’t feel bad if you’re confused. Barrel-aging liquor is one of the least understood, most elusive elements that goes into all of your favorite drams. A year isn’t always a year. Some years are more valuable than others.
How to make sense of it all? Here’s a primer on what to look for when seeking out the best aged spirits.
In theory this is correct. Historically, the barrel has provided the brown/gold color of aged spirits. The longer the liquor aged, the darker it got. This occurred because the water and ethanol that makes up a spirit leaches out tannins and other darker-hued elements from the barrel’s staves.
This rule of thumb still works today, but with more asterisks than the Milky Way. Some spirits are aged for a few years in barrels, and then filtered to remove the color. (Silver Bacardi rums, for instance.) Other spirit producers will make a young product look older (legally) by adding caramel coloring.
Aging doesn’t necessarily improve liquor—it only changes it. A whiskey that’s spent three years in a cask will taste very different from the same distillate that’s had eight years in a barrel. Yet you might prefer the younger to the older—it’s all a matter of taste. However, it’s a good bet the older will be more expensive—lots of capital is tied up in letting sleeping barrels lie, and those costs are, naturally, passed on to the consumer.
You are no doubt already aware that spirits and wine are very different beasts. Lower-proof, yeasty wine is still very much alive when it’s bottled. The flavor thus continues to evolve and at some point wine will pass its prime.
Spirits, in contrast, age only when in a barrel. Distillation strips out the yeast and the higher alcohol levels stabilize the liquid. When it moves from barrel to bottle, the liquor becomes relatively inert—the flavors hardly alter over time.
Assuming that a bottle doesn’t have a faulty cork or cap (exposure to air can degrade it), a whiskey bottled in, say 1935, will taste, by and large, the same today as when it was bottled in 1935. (Light and the slight presence of oxygen in the headspace can result in some subtle evolution of flavor.)
Barrels started out centuries ago as handy storage and shipping containers. But spirits traders early on noted that the flavor often improved when spirits spent time fraternizing with barrel staves while in transit.
Two things happen in a barrel: first, the spirit picks up some of the flavor of the wood, which in the vast majority of cases is made of white oak. Virtually all barrels are toasted or charred before use—the heat caramelizes some of the natural sugars in the wood, which can account for the butterscotch notes. And wood elements like lignin are chemically changed by heat to create chemicals called phenolic aldehydes, which can add flavors resembling vanilla.
Also, barrels are not fully airtight—they mostly keep the liquor in, but also allow oxygen to penetrate where the staves meet and through pores in the wood. (Barrels do slowly empty as vapor from the spirit escapes—about five percent a year in temperate climates.) Over time—it can take years—the oxygen interacts chemically with the distillate to create long-chain molecules and more complex flavors that are desirable in an aged spirit.
So barrels are essentially nano-factories—they have the means to alter the liquid at a molecular level, making it more complex.
Note that not all barrels are the same. A new barrel has far more flavor elements than a used one. Federal law requires that bourbon be aged in new oak barrels, which helps explain why many bourbons are so redolent of vanilla. Once used, the barrel is usually sold to makers of other spirits. Scotch distillers like once-used barrels because whisky made from barley is more delicate than the corn whiskey of bourbon, and would be overpowered by flavors in new wood.
No. When liquor makers do this, it’s usually for marketing purposes, not legal requirements. In fact, “age statements” on labels have become less common lately. The reason? Stocks of aged spirits have been depleted thanks to the high demand and low supply of quality aged products.
Many makers of aged spirits have chosen to empty barrels at a faster rate than they’d anticipated, and the find it’s easier to eliminate the age statement than lower the year on the label—which could potentially confuse or annoy customers. Cynics will note that by dropping the age statement, producers can also sell spirit aged for fewer years for the same cost as a longer-aged spirit.
Before many spirits are bottled, the barrels in which they aged are combined together—often the contents of dozens of different barrels are mixed in a large vat. The blender’s goal is quality, not necessarily to graduate a barrel class simultaneously. They’re seeking a balance of flavors, and different notes emerge during different parts of the aging cycle.
If a producer does choose to print an age statement, the year must reflect the youngest spirit contained in the bottle; per paragraph 5.41 of Part 5 of Title 27 of the Code of Regulations (because you asked), “Age may be understated but shall not be overstated.” For instance, in a bottled labeled as an eight-year-old bourbon, the blender may have opted to give it more body and nuance by adding small amounts of 10 or 12-year-old spirit.
This doesn’t apply to spirits labeled bottled-in-bond, which are filled from spirits all made the same year (and have been aged at least four years), nor to “single-barrel” spirits, which, as the name suggests, are the contents of a single barrel.
Owing to a series of arcane federal regulations, there are also a few other terms that are essentially code words for how old a spirit is if a year is not listed on the label. Chief among these is the term “straight whiskey.” This indicates that it has spent at least two years aging in new oak. (If the aging period was between two and four years, the number of years must be printed on the label—an exception to the no-federal-requirement mentioned above.)
Actually, no. Not only will a new barrel age its contents at different rates than a used barrel, but the location where the barrel is stored can make a significant difference.
Barrels stored in warmer climates age at a faster rate than those stored in cooler places. Heat speeds chemical reactions, while also leading to larger pressure differentials inside the barrels, which forces the liquid deeper in the wood to extract more flavors. Barrels essentially take winters off—not much happens inside a barrel when temperatures plunge. As a result, it takes longer for liquor aged in cooler Scotland to reach maturity than in warmer Kentucky. The late Dave Pickerell, former Maker’s Mark distiller and a craft industry consultant, once swapped barrels with a Scotch distiller, and after regular samplings concluded that one year of aging in Kentucky was equal to about three or four years of aging in Scotland.
So you often see Scotch that’s been aged 12 or 18 years, which is fairly rare in bourbons, which is typically aged six to eight years. And rums aged in the even warmer Caribbean typically undergo shorter aging still. In Mexico, tequila is considered aged after only a single year in a barrel. After three years it can be labeled as “extra old.”
Do carefully examine the label. Look for a number followed by the word “years.” Look for phrases such as “straight” and “bottled-in-bond,” which indicated minimum aging. Be wary of prominent numbers that make no reference to years—some crafty producers print a large numeral to lead you to think that refers to the minimum aging periods. (Looking at you, Ron Zacapa 23). A number can be part of a brand name, or it may refer to an obscure production technique, not the age.
Google is your friend. A search can help you sort out some of the minimum aging requirement linked to various terms, such as tequila designations, as well as for Cognac and Armagnac—if it says V.S. on the label, for instance, it’s been aged at least two years.
But the bottom line is this: it’s all about taste and your preferences. Some prefer the complex oaky taste that emerges and dominates long-aged spirits. Some prefer their liquor to taste more of the base ingredient—like grain in rye, or agave in tequila.
Your homework: Go to a bar and ask for a vertical flight of your favorite spirit—same brand, different age statements. Sip. Enjoy. Return to those you like best.
Well done. A+.