Why Is Oak Used for Aging Wines?

Oak barrels provide more than a simple means of wine storage; they play an integral part in the aging process and impart distinct sets of flavors to some truly fine wines. Oak helps age wines by slowing the integration of oxygen, softening tannins, and deepening color intensity. Winemakers may select from various-sized barrels depending on regional laws, the desired style of wine production, and the intuition of their viticulturalist. In this blog post, we’ll delve into the reasons why oak is used for aging wines, the types of oak commonly employed, and the significance of choosing the right barrel for aging wines.

The Magic of Oak Aging

oak barrels

Oak barrel aging is a centuries-old practice that has become synonymous with wine craftsmanship. As early as ancient Mesopotamia, winemakers realized that wooden barrels used for transporting their products provided their wines with added qualities; since then, the practice of aging wines in oak barrels has continued. Contact between wine and wood promotes additional aromas, reduces tannin acids, and can even cause lactic fermentation – turning malic acid into creamy-tasting lactic acid!

Here’s why oak is the preferred choice for making an aging barrel:

1. Flavor Enhancement

Oak plays a vital role in imparting distinct flavors and aromas to wines. As the wine undergoes the aging process, it interacts with the wood, absorbing various compounds such as vanillin, lactones, and tannins. The wood is rich in chemical compounds and aromatic molecules that confer specific traits to the wine, ranging from vanilla to coconut, dill, or spice. The resulting flavors are influenced by the type of oak and its treatment, including toasting or lack thereof. These phenolic compounds are released when the oak is exposed to air and subsequently transferred into the wine, enhancing its complexity.

2. Oxygen Exchange

Oak barrels are crucial in wine production as they enable a controlled process of slow oxidation and evaporation, leading to the softening of tannins and aiding in color stabilization. This controlled interaction with the oak contributes to a more balanced and nuanced wine development. It’s not only the physical attributes of oak barrels that matter; their chemical components play a significant role in imparting flavors and aromas to the wines that age within them.

Oak barrels allow a controlled exchange of oxygen between the wine and the environment. This gentle oxidation process helps soften harsh tannins and integrates the wine’s flavors, resulting in a smoother and more balanced taste.

3. Microbial Activity

Oak barrels are home to beneficial microorganisms that can contribute to wine fermentation and maturation. These microorganisms can influence the wine’s aroma and flavor profile.

4. Texture and Mouthfeel

Cellulose and lignin present in wood can interact with proteins and polyphenols present in wine to alter texture and aroma characteristics. Furthermore, oak’s natural tannins help soften its astringency and produce smoother mouthfeels in red wines. Oak barrel aging plays a great role in maintaining overall balance within wines and plays an integral part in many winemaking styles – particularly red.

What types of oak are used for wine?

Oak serves to enhance the body and structure of lighter red wines, offering the essential framework for long-term aging. The type and toasting level of the oak play a pivotal role in determining the strength or subtlety of flavors in the final wine product.

White (Quercus alba) and red oaks are the two primary species used for aging purposes, both having distinct characteristics suited to various applications. White oak is more resistant to rot and water damage, while red oak boasts rustic charm with wide grain rays running through its wood grains.

1. French Oak

   – Flavor Profile: French oak imparts delicate and complex flavors such as vanilla, spice, and subtle toastiness.

   – Popular for high-quality wines like Bordeaux and Burgundy.

2. American Oak

   – Flavor Profile: American oak provides stronger flavors with pronounced vanilla, coconut, and dill notes.

   – Popular for many California wines, including Zinfandel and Chardonnay.

3. Hungarian Oak

   – Flavor Profile: Hungarian oak offers a balance between French and American oak, with vanilla and spice notes.

   – Popular for a range of European and New World wines.

4. Slovenian Oak

   – Flavor Profile: Slovenian oak is known for its subtlety, contributing mild flavors of vanilla and floral notes.

   – Popular for wines from Eastern Europe, including Italian and Slovenian varieties.

Oak is sourced from various regions worldwide, with France and the USA being renowned for their superior oak. Additionally, Hungary, Austria, and Russia also produce high-quality oak. Modern winemakers are increasingly opting for shorter aging times to limit oak characteristics in their wines. This shift aligns with consumer preferences for fruitier wines, often without the pronounced oak influence.

Choosing the Right Barrel for Aging

The wood used for wine aging is becoming more diverse as winemakers and coopers look beyond the more common species to find unique ones that provide unique aromas that complement wines produced in those barrels. Some examples include Castanea sativa, Robinia pseudoacacia, and Fraxinus excelsior, although these species may not be used as frequently.

Selecting the appropriate type of barrel is a crucial decision in the winemaking process. Winemakers often consider factors like oak origin, barrel size, and toast levels to achieve the desired flavor and aroma characteristics.

Old vs. New Barrel For Aging

Although most wine is aged in large oak barrels for sale, known as Barrique today, many top winemakers utilize both old and new oak to balance out various impacts on their wines. For instance, new oak has been known to open up white wines while sublimating red tannic structures, giving wines greater flexibility while keeping them balanced and refreshing.

Oak Origin

The choice of oak used in barrels is critical, as different oak species contain distinct phenolic compounds that influence the aromas and flavors of the wine in diverse manners. French oak barrels, for instance, often introduce more clove, cinnamon, and vanilla aromas compared to their American counterparts. This disparity arises from variations in wood density and the toasting process applied to the wood pieces. Each type of oak presents a unique flavor profile, and the selection depends on the desired style of the wine.

Barrel Size

Size also plays an essential role in oak barrel aging. Oak barrels come in various sizes, from 225-liter Barriques up to larger 500-gallon Botti and Foudres; smaller barrels tend to have a greater impact as more wine comes into contact with their wood surface. Smaller barrels have a higher surface area-to-volume ratio, leading to faster oak extraction. Larger barrels are used for more gradual aging. A typical 225-liter barrel tends to shed a certain percentage of its volume over the course of one year, intensifying aromas and flavors within.

Toasting Levels

Winemakers have the ability to tailor the toasting process to influence the intensity of flavors. Toasting leads to the release of specific phenolic compounds present in the wood. Once burned away, different phenolic components are left behind. This aspect is a key distinction between American and French barrels. Light toasting can emphasize fruitiness, whereas heavy toasting can accentuate more pronounced oak flavors.

Final Thoughts

Oak barrels for sale are an expensive piece of winemaking equipment. They are composed of straight, solid pieces of wood called staves that need to be softened with heat before they can be bent into their final shape for holding wine in order to be used effectively. Traditionally, this was achieved by heating them over an open fire; this gave certain flavors and even helped hide wine color. Nowadays, the heating process is more closely controlled, enabling winemakers to select an oak style that best complements their desired flavor profiles.

Noteworthy is the impact that the type of barrel has on wine flavor, with smaller barrels imparting more oak notes due to having a greater surface area of contact than larger barrels. Age can also have an effect, as older ones allow oak flavors to mellow over time while newer barrels give winemakers more of a boost compared to their predecessors. All these variables combined make finding a suitable match between size, age, type, and origin can be an art in itself!


Rachel Moore works as a Marketing Manager at RMBC. RMBC provides used wooden barrels for spirits, like bourbon barrels, whiskey barrels, rum barrels, and wine barrels. They are proud to partner with 1400+ breweries internationally.