Have you ever stood in a wine shop or restaurant and come across terms like “aged in oak” or “barrique”? Chances are you’ve wondered what exactly oak aging does to the wine in your glass. Why does a winemaker choose wooden barrels instead of stainless steel tanks? And what effect does it have on the taste of the wine?
There are many misconceptions surrounding wine and oak aging, but it doesn’t need to be a mystery. At the Amsterdam Wine Academy, we receive these questions all the time — and rightly so, because oak aging is one of the most fascinating aspects of winemaking and wine maturation. In this article, you’ll discover everything about the influence of oak aging on wine: how it affects aroma, tannins, texture, longevity and why it’s such an essential topic in wine education programs like WSET.
What Exactly Is Oak Aging?
Oak aging is the process in which wine matures in wooden barrels, usually made of oak. This aging process typically takes place after fermentation (or sometimes during it). Winemakers choose oak aging deliberately to add extra complexity, structure and depth to the wine.
A barrel is not a passive storage vessel. The wood breathes, allowing a tiny amount of oxygen to enter the wine over time. At the same time, the wood releases aromas, tannins and texture into the wine. This process is known as maturation in oak or barrique aging, with barriques referring to small barrels of 225 liters. The larger the barrel, the less contact the wine has with the wood, which directly influences flavor.
Why Do Winemakers Age Wines in Oak?
- Aroma and flavor: Oak imparts aromas such as vanilla, coconut, toast, smoke or clove. These integrate with the wine’s natural aromas, creating a more complex bouquet and taste profile.
- Softer tannins: In red wines, oak barrels help soften firm, harsh tannins, making the wine rounder and more approachable.
- Micro-oxygenation: The controlled exposure to oxygen allows wine to develop more quickly and more elegantly.
- Natural clarification: During barrel aging, particles sink naturally to the bottom, contributing to greater clarity and stability over time.
- Improved longevity: The subtle oxidative effect stabilizes the wine and often increases its aging potential.
Different Types of Wood and Their Impact
The choice of wood has a significant influence on the wine. Most winemakers use oak, but there are important differences between American and French oak.
American oak (Quercus alba) has a coarser grain structure than European oak and imparts pronounced aromas of vanilla, coconut and caramel. Because of its more open grain, wine tends to mature faster in American oak.
French oak (such as oak from the Tronçais forest) has a much finer grain and contributes more subtle aromas of toast, spices and gentle oak notes. These barrels are known for adding elegance and refinement to the wine.
Winemakers sometimes choose barrels that have already been used for several years, in order to reduce the intensity of oak influence. New oak releases much stronger flavors into the wine compared to older barrels.
The structure of the growth rings and the tightness of the grain — in addition to the type of oak — also play an important role. These factors partly explain why wines from different parts of the world can have noticeably different oak characteristics. While a French winery can certainly use American oak, in practice you often see producers choosing wood sourced from their own region.
The Role of Toasting
Before the wine enters the barrel, the oak is heated over an open flame — a process known as toasting. Depending on the intensity of the toasting, different flavor profiles are created:
Lightly toasted barrels: Subtle notes of vanilla and gentle roasted aromas.
Heavily toasted barrels: Deeper flavors such as coffee, cocoa and smoke.
The level of toasting is therefore a crucial factor in determining the final aroma and flavor of the wine. Moisture in the wood fibers is not beneficial for the wine, which is why oak is often dried — either naturally or through controlled, artificial drying — before being used.
What About White Wine?
Although the vast majority of white wines are fermented in stainless steel, there are notable exceptions. Especially with oak-aged Chardonnay, part of the wine is often fermented in an oak barrel or oak tank. This adds structure, buttery aromas and a creamy mouthfeel.
A well-made white wine can certainly be matured in a wooden barrique to add extra complexity. However, oak aging in white wine is a delicate craft: if overused, the oak notes can easily overwhelm the wine and spoil its balance.
What Should You Pay Attention to as a Wine Lover?
Not every wine benefits from oak aging. Young wines with lots of fruit aromas or delicate acidity can lose their freshness. In some cases, oak aromas are poorly integrated into the wine—especially in cheaper wines that use oak chips instead of real barrels.
Therefore, pay attention to the following factors:
- Duration of oak aging: The longer the wine spends in oak, the stronger the influence.
- Barrel size: Smaller barrels (e.g., 225-liter barriques) provide more wood contact and therefore more oak character.
- Origin of the oak: American oak vs. French oak can lead to very different flavor profiles.
- Number of times the barrel has been used: New barrels impart strong flavors; barrels used for several years give a much more subtle influence.
Wine Education: Learning About Oak Aging Yourself
At the Amsterdam Wine Academy, our WSET programs teach you everything about oak aging, the relationship between wine and wood, and the decisions winemakers make throughout the process. Our instructors are experienced vinologists, sommeliers and WSET-certified professionals with many years of practical industry experience. Whether you are a wine professional or a passionate enthusiast, you will learn to truly understand wine.
- WSET Level 1 in Wine: Learn the basic principles of wine and discover the influence of oak aging.
- WSET Level 2 in Wine: Dive deeper into oak aging techniques, barriques and the stylistic decisions winemakers make for each grape variety and wine style.
- WSET Level 3 in Wine: Select the best wines for every occasion and dish, and develop even more advanced techniques in smelling, tasting and enjoying wine.
View the full range of programs offered by the Amsterdam Wine Academy on this page.
Frequently Asked Questions About Oak Aging
1. Why do winemakers choose oak aging instead of stainless steel?
Oak aging adds complexity, additional aromas and a softer, rounder structure. Stainless steel tanks preserve freshness and fruit, which is ideal for young wines and most white wines. Depending on the wine style and intended outcome, winemakers choose the method that best suits the wine.
2. Does the size of the barrel matter?
Absolutely. The smaller the barrel (for example, 200–225 liters), the more contact the wine has with the wood, resulting in a stronger oak influence. A larger barrel of 500 liters imparts less “character,” which can actually be beneficial when working with new oak.
3. What is the difference between fermentation in oak and aging in oak?
Fermentation in oak means that the alcoholic fermentation takes place inside a wooden barrel, adding extra structure and texture to the wine. Aging in oak happens after fermentation and primarily influences aroma development and tannins. Fermenting in a tank produces a very different flavor profile compared to fermenting in a wooden barrel.
Why Choose Amsterdam Wine Academy?
- Official WSET provider in the Netherlands
- Experienced professionals with years of hands-on expertise
- Small groups with lots of personal attention
- Centrally located in Amsterdam
- Course materials available in both Dutch and English
We make wine knowledge accessible and fun—whether you’re just starting out or have been exploring the wine world for years.
Want to dive deeper into the influence of oak aging and finally understand why some wines have more layers and depth than others?
Sign up for a WSET course at Amsterdam Wine Academy and discover the world of wine in a whole new way.
Let wine no longer be a mystery. Become a conscious wine drinker. And who knows—maybe soon you’ll be able to recognize the subtle influence of that one special barrique from the forest of Tronçais.
