Wine aromas come from three main sources (the grape, fermentation, and ageing ), but it is the barrel that plays a decisive role in the final aromatic profile of high-quality wines. Primary aromas originate in the grape variety itself (fruit, floral, vegetal or mineral notes), secondary aromas are created during fermentation (bakery, dairy and fruity estery notes), and tertiary aromas appear with ageing, especially when the wine is in contact with wood. The type of oak and the toast level of the barrel directly influence the development of spicy notes, vanilla, toasted nuances or greater structure, adding complexity and integration without masking the wine’s identity.
What are wine aromas and why are they not the same as wine flavour?
When we talk about wine aromas, we are referring to the olfactory sensations we perceive through the nose before and during tasting. These are volatile compounds released in the glass that directly stimulate our olfactory system.
Wine flavour, on the other hand, is a much more limited perception. The tongue can only identify five basic tastes: sweet, sour, salty, bitter and umami. Everything else (fruit, spices, toast, flowers, leather or vanilla) is not flavour in the strict sense, but aroma.
So why do we often feel that we “taste” those nuances?
Because the retronasal pathway comes into play. When wine is in the mouth, aromatic compounds rise to the nasal cavity through the back of the palate. The brain combines that olfactory information with taste and tactile sensations (acidity, tannin, alcohol, body), creating the overall perception we usually call “flavour.”
In reality:
- Taste provides structure (sweetness, acidity, bitterness).
- Smell provides complexity and nuances.
- Texture provides sensations such as body, volume or astringency.
That is why a wine can have marked acidity (a gustatory sensation) while standing out for its aromas of tropical fruit or spices (an olfactory sensation). It is also why, when we have a cold and lose our sense of smell, wine seems flat and characterless.
The three main groups of wine aromas
Although the aromatic nuances of wine can be practically endless, from a technical point of view they are classified into three main groups. This division makes it easier to understand where wine aromas come from and how they develop throughout winemaking and ageing.
| Type of aroma | Where does it come from? | When does it originate? | Common examples |
|---|---|---|---|
| Primary | From the grape variety | Before and during harvest | Fruit, flowers, vegetal notes, minerals |
| Secondary | From the fermentation process | During alcoholic and malolactic fermentation | Bakery notes, dairy notes, banana, yeast |
| Tertiary | From ageing and maturation | During barrel and bottle ageing | Spices, toasted notes, leather, nuts |
Primary aromas: what the grape contributes
Primary aromas are those that come directly from the grape. They are inherent to the variety and depend both on the genetics of the vine and on the climate, soil and time of harvest.
They are usually divided into several aromatic families (floral, fruity, vegetal and mineral). For example, we may find notes of jasmine or rose in certain white varieties, red fruit in many reds, or mineral impressions linked to the terroir.
These aromas are more evident in young wines, where fruit and varietal expression take centre stage.
Secondary aromas: how they are created during fermentation
Secondary aromas are generated during the fermentation process. Yeasts, temperature, the type of tank and the winemaking decisions made in the cellar all play a role here.
During alcoholic fermentation, notes related to bakery or pastry may appear (bread crumb, brioche). If malolactic fermentation takes place, dairy aromas may develop (yoghurt, butter, fresh cheese).
These aromas do not come from the grape itself, but from the chemical transformation of its sugars and acids.
Tertiary aromas: where ageing aromas come from
Tertiary aromas appear during the ageing of the wine, whether in barrel or in bottle. They are also known as bouquet.
At this stage, more complex and evolved notes develop, such as spices, wood, toasted nuances, nuts and leather. They result from the interaction between the wine, oxygen and, in many cases, wood.
These aromas are usually associated with wines intended for longer ageing and with high-quality wines that have undergone a controlled maturation process.
The barrel and its direct influence on the aroma of high-quality wines
When people talk about aromas of vanilla, clove or spices, many assume they come directly from the grape. However, a fundamental part of these nuances does not come from the vineyard, but from the barrel.
The barrel is not just a container. It is an active tool that transforms the wine. Depending on the type of oak, its origin and the level of interior toasting, the wine will develop a different aromatic profile — finer and more elegant, or more structured and powerful.
In high-quality wines, the choice of barrel is a strategic decision. It is not just about ageing the wine, but about adding complexity, balance and aromatic depth without masking the fruit.
At Tonelería Murúa, the selection of oak and the control of the manufacturing process are an essential part of the final result in the glass. Each barrel is conceived according to what the winery wants to express in its wine.
American oak: vanilla, coconut and greater structure
American oak barrels are known for providing more obvious and sweeter aromas. Among the most characteristic are vanilla and coconut, derived from compounds such as whisky lactones.
They tend to contribute to wines with a greater sense of structure and volume. Their aromatic impact is more direct, which can be ideal when a more marked and recognisable profile is desired.
French oak: elegance, spice and respect for the fruit
French oak barrels are characterised by offering subtler, spicier aromas. Notes of white pepper, clove or slightly balsamic hints are common.
They are usually associated with wines, where the wood accompanies without dominating and shows greater respect for the fruity expression of the grape.
Its finer grain and structural composition allow for a more gradual release of aromatic compounds, encouraging complexity without saturating the wine’s profile.
The choice between French and American oak is not a question of quality, but of style. Each gives the wine a different personality.
Barrel toasting and its impact on wine aromas
In addition to the origin of the oak, the interior toasting of the barrel is crucial in the development of aroma.
During the manufacturing process, the wood undergoes controlled toasting that may vary in intensity (light, medium or plus). This heat treatment alters the compounds in the wood and defines the type of aromas that will be released during ageing.
- A light toast preserves more freshness and respects the fruit.
- A medium toast balances structure and spicy notes.
- A more intense toast enhances sweeter, more marked aromas (vanilla, caramel, toasted notes).
At Tonelería Murúa, controlling the toast is a key stage: we toast the inside of the barrel for between 90 and 180 minutes and adjust the level (light, medium or plus) according to each winery’s needs, in order to bring sweeter aromas (vanilla), spicier notes or a more balanced profile to the wine.
How wine aromas develop during ageing
Ageing is a decisive stage in the aromatic evolution of wine. During this period, the wine not only stabilises and becomes rounder on the palate, but also develops new aromatic nuances that increase its complexity.
This process is mainly driven by three factors: contact with wood (if the wine is aged in barrel), micro-oxygenation, and the passage of time.
When wine remains in a barrel, a slow and controlled exchange of oxygen occurs through the pores of the wood. This micro-oxygenation encourages chemical reactions that soften tannins and allow the gradual integration of the primary and secondary aromas with the aromatic compounds from the oak.
As ageing progresses, fresher fruity aromas may evolve into riper or stewed notes. Spicy, toasted or balsamic nuances appear, and the whole becomes more harmonious. The point is not to replace the fruit, but to integrate it into a more complex structure.
During bottle ageing, the process continues. In the absence of oxygen, the wine evolves toward more delicate tertiary aromas such as leather, nuts and tobacco. This bouquet is the result of the combination and transformation of earlier aromas.
The aromatic development during ageing is neither linear nor automatic. It depends on many variables: type of wine, initial structure, type of barrel, time spent ageing, and storage conditions. That is why, in high-quality wines, ageing is a technical decision aimed at enhancing the wine’s identity rather than masking it.
Positive aromas and wine faults: how to tell them apart
In the sensory analysis of wine, not all aromas have the same meaning. Positive aromas are those that add complexity, identity and balance to the whole (fresh or ripe fruit, floral notes, spices, toasted nuances and nuts). They are well integrated and help make the wine harmonious.
Faults, on the other hand, create unpleasant sensations and are usually linked to problems in production, storage or closure. Among the best known are cork taint (TCA), oxidation (reminiscent of stale wine or over-aged nuts), reduction (egg or sulphur smells), or high volatile acidity (vinegar). The main difference lies not only in the type of aroma, but in its balance and integration within the wine.
How to train your sense of smell to identify wine aromas accurately
Recognising wine aromas accurately is a skill that develops with practice. Olfactory memory works by association, so the wider our range of references (fruits, spices, flowers, woods), the easier it becomes to identify them in the glass.
During tasting, it is advisable to smell the wine first without swirling and then again after moving the glass, as this releases more complex aromatic compounds. Comparing different styles and varieties also helps us understand how the grape, fermentation and ageing influence the aromatic profile. Over time, the sense of smell becomes more precise and the tasting experience more complete.
