Spanning centuries, continents, oceans, and kings, the story of how American oak barrels became an iconic component of Spanish wines is as much an account of one nation’s vinicultural development as it is a revealing look into the socioeconomic history of colonialism itself.
No other Old World winemaking region is as closely aligned with the unique sapid imprint of American oak aging as Rioja. Located in Northern Spain’s Ebro River Valley, Rioja is hailed worldwide for its Tempranillo-dominant reds and Viura-dominant whites that are, upon release, among the longest-aged in the world. Reserva-designated reds carry a mandatory minimum aging of three years, with two years required for whites, while Gran Reservas—the loftiest available imprimatur—see a minimum of five years of aging for reds and four years for whites.
It should be noted, however, that most producers view these timeframes as mere baselines. It is not at all uncommon for exceptional Riojas to reach the marketplace with 5-10 years of additional age—a sure sign of the region’s commitment to high-quality, well-integrated wines ready for drinking upon release, yet also poised for decades of additional cellaring.
But age, terroir, and inimitable native grapes are hardly the only factors differentiating Rioja wines in an increasingly crowded, globalized marketplace. Simply put, it is not just the patient time spent in wait—impressive as it is—but the particular flavor compounds, tannins, and aromas derived from American oak that help to put the finishing touch on wines of such extreme complexity.
What Is American Oak, and Why Does It Matter?
The Quercus alba tree, commonly known as white oak, is one of the strongest and longest-living hardwood varieties of the temperate Northern hemisphere. Native to the forests of Eastern and Central United States—where it is found in abundance—white oak is resilient, easy to work, and relatively lightweight. Despite being less finely grained than its main cooperage counterpart, French oak (Quercus robur), Quercus alba is paradoxically more liquid-tight due to its preponderance of “tyloses,” or structures that plug the tubes of the wood and prevent leakage.
An historical mainstay of winemakers and distillers for hundreds of years, it would be difficult to imagine a more perfect wood for cooperage, cask-aging, and transport than American oak—but that’s only part of the story. Choosing what kind of wood to use is as much a practical decision as it is an aesthetic and sensory one. Not only are new barrels often expensive and thus reserved only for the highest quality and most age-worthy wines, the provenance of a winemaker’s cooperage can also have a substantial effect on the flavor, style, and approachability of their finished wine.
French oak, for example, is known for its subtle spice notes and is often best matched to wine grape varieties like Pinot Noir and Chardonnay. American oak, with its rich, expressive notes of vanilla, coconut, and dill, pairs best with bolder varieties like Tempranillo and Cabernet Sauvignon. Extended oak aging also allows the intensity of a wine’s flavors to develop, soften, and enmesh, as the permeability of the barrel’s staves allows for a gradual micro-oxygenation.
Rioja in the Age of Exploration
So how did wood sourced from what was then a sparsely-inhabited wilderness more than four thousand miles away come to define one of the world’s most noble wines, while also deeply impacting the history of Old World viniculture? The short answer: longstanding Spanish trade routes mapped throughout the Age of Exploration.
While viticulture on the Iberian peninsula predates both the Romans and the Phoenicians—with vines cultivated as far back as 2000 BCE—most ancient production resulted in wines sought-after for the longevity conferred by their high alcohol content, itself a function of the region’s warm climate. Noted for their shelf-life, Spanish wines had found their first of many subsequent advantages over their French and Italian counterparts, even if at the time they were hardly considered the preferred pours of royal courts or aristocrats
In the 15th century, however, a newly unified Spain embarked on an ambitious exploration of the New World. What resulted was an entirely novel economy of transatlantic trade, which saw the acquisition of vast amounts of raw materials, the spread of Spanish vines to the Americas via missionaries and conquistadors, a marked increase in the ranks of the mercantile class, the establishment of a new export market for Spanish wines, and, ultimately, the creation of a previously untapped import trade of American oak.
By the 16th century, the wines of Rioja had established an international reputation exceeding their earlier distinction as hardy, durable quaffers, traveling now to grateful drinkers as far away as any Spanish clipper could carry them. But as maritime colonial trade increased, so too did naval tensions with England, one of the superpowers of the age—not to mention one of Spain’s other most important export markets. With escalating tensions came war, with war came defeat, and with defeat came debt. Following the rout of the Spanish Armada in 1588, a financially sobered Spain found its wine trade on rocky footing. A roller coaster ride of economic vicissitudes ensued, even as the popularity of Rioja increased appreciably throughout the seventeenth and eighteenth centuries.
French oak was excessively expensive, so a cash-strapped Spain looked to its current—and in some cases former—colonial holdings in the Americas to source a solution. Over time the independent countries that had quietly sprung up in both North and South America remained a sizable export market for Rioja and, moreover, were neutral trading partners an ocean away from Europe’s internecine struggles. Add to this that the Americas were awash in Quercus alba and the picture becomes clear: where financial hardship demanded a clever fix, an auspicious pairing of flavorful American oak and the bold grape Tempranillo led the way to a renaissance of Spanish wine.
The distinctiveness and balance of this new style of Rioja satisfied local drinkers who had not for many years enjoyed high quality domestic wines, while the use of lightweight, economically sensible cooperage satisfied merchants and shippers. What was unforeseen, perhaps, was quite the magnitude to which Tempranillo and Quercus alba could form a holy union wherein the foreign wood tamed the inimitable local grape, while the grape in turn matched and elevated the wood’s hard-to-balance flavors.
While many modern producers began to adopt French oak in the latter half of the twentieth century, the classic style of red Rioja—muted red fruit, soft tannins, well integrated acidity, and heady aromas of vanilla, dill, and cedar—dates back to a tangled history of transatlantic trade that helped to create what is still to this day one of the classic wines of the world.