Wine Aroma: The Language Of Wine Connoisseurs

Wine aroma, or nose, is the smell of the wine in the glass. The human nose can distinguish thousands of unique scents, and it is our olfactory abilities that allow us to discern the variety of flavours in a single sip. The tongue, on the other hand, is limited to sensing salty, sweet, bitter, and sour. Wine aromas can be floral, citrus, fruity, vegetal, or earthy, depending on the grape variety, winemaking process, and storage conditions. Kevin Zraly, a wine educator and author of the primer Windows on the World Complete Wine Course, advises keeping it simple when it comes to tasting notes.

Wine aromas are more diverse than flavours

The aromas of wine are more diverse than its flavours. While the human tongue is limited to the primary tastes perceived by taste receptors—sourness, bitterness, saltiness, sweetness, and savouriness—the complex aromas of wine are sensed by the olfactory bulb.

Wine aromas are influenced by a variety of factors, including the grape variety, winemaking processes, and storage conditions. Primary aromas are derived directly from the fruit itself and are typically found in young wines, with floral and fruity scents being common. Secondary aromas are influenced by the winemaking process, with oak being a dominant factor, imparting nutty, buttery, vanilla, and woody notes. Tertiary aromas develop as wine ages, with longer ageing leading to more pronounced oxidative traits like coffee, caramel, toffee, cocoa, and earthy notes.

The act of wine tasting involves both smelling and tasting, with the nose playing a crucial role in differentiating the diverse scents. The technique of swirling the wine in the glass releases volatile aroma compounds, enhancing the aromatic experience.

The wide array of wine aromas includes fruity, floral, earthy, leathery, herbal, mineral, and woody notes. These aromas are derived from volatile and non-volatile compounds present in the grapes, which interact with sugars and other components during fermentation and ageing, creating a complex array of scents.

The study of wine aromas and their correlation with flavour and quality is an ongoing area of research. The understanding of these compounds raises concerns about potential future manipulation of wine aromas through chemical additives. However, it also highlights the importance of using one's sense of smell when tasting wine, as it greatly enhances the overall tasting experience.

The human nose can differentiate thousands of unique scents

The human nose is an incredibly powerful tool when it comes to differentiating scents. While it has long been believed that humans could only distinguish around 10,000 different scents, new research has revealed that this number was a vast underestimate. In fact, the human nose is capable of differentiating between thousands, if not millions, of unique scents, with some studies suggesting a figure of at least one trillion.

This extraordinary ability to discern smells is due to our olfactory system, which is far more sensitive than previously thought. We have upwards of 400 different smell receptors working in harmony, allowing us to detect a vast array of aromas.

When it comes to wine, our sense of smell plays a crucial role in the tasting experience. The aromas of wine are diverse and complex, ranging from fruity and floral to earthy and woody notes. By swirling the wine in the glass before taking a sip, we release volatile aroma compounds, which our noses then detect. This is why wine drinkers often smell the wine before tasting it, as it helps to identify some of the components and enhances the overall tasting experience.

The act of tasting wine involves a delicate interplay between the senses of smell and taste. While the tongue is limited to detecting primary tastes like sourness, bitterness, saltiness, sweetness, and savouriness, it is the nose that picks up on the intricate flavour scents. This is why wine tasters often spend time sniffing the wine, trying to identify the various aromas before taking a sip.

The process of fermentation further adds to the complexity of wine aromas. During fermentation, chemical reactions between acids, sugars, alcohols, and phenolic compounds create new smells known as the wine's bouquet. These can include notes of honey, truffles, coffee, caramel, and cocoa, which develop over time as the wine ages.

In conclusion, the human nose is a powerful tool that can differentiate thousands of unique scents, and when it comes to wine tasting, it is an essential component that enhances our enjoyment and understanding of the complex aromas and flavours present in each sip.

Primary aromas come from the grape variety itself

The primary aromas of wine come from the grape variety itself. These aromas are almost always fruity, but not always. They may also be floral in nature. Violets, rose, chamomile, green apple, citrus, black and red berries would all fall under the primary aroma category.

The grape aroma is synthesised in grape berries by a variety of enzymes, including terpene synthases, O-methyl transferases, carotenoid cleavage dioxygenases, and cytochromes P450. The genetic variation in aroma biosynthesis genes causes differences in aroma between grapevine varieties. For example, an allelic variant of 1-deoxy-D-xylulose-5-phosphate synthase, a terpenoid biosynthetic gene, causes the accumulation of terpenoids in Muscat and Gewürztraminer grapes. The abundance of terpenoids gives these wines a distinct floral aroma.

Monoterpenes are one of the largest and most researched wine aroma compounds. They are responsible for the floral and citrusy notes in many wines. For example, monoterpenols and their derivatives give Muscat and Gewürztraminer wines their characteristic aromas.

The volatile compounds that constitute wine aroma are traditionally divided into three classes according to their origin: grape, fermentation, and maturation aroma. However, these three classes are not always distinct. Ultimately, most aroma precursors, even the simple ones, originate from grapes and are modified in some way by the fermentation process or ageing.

Secondary aromas are derived from the winemaking process

When it comes to wine, the nose knows. The human nose can distinguish between thousands of unique scents, and it is our olfactory abilities that allow us to discern the variety of flavours in a single sip.

Wine aromas are typically split into three categories: primary, secondary, and tertiary. Primary aromas are derived from the grape variety itself, such as fruit and floral smells. Secondary aromas are derived from the winemaking process, and include influences such as oak ageing, malolactic fermentation, and lees ageing.

Secondary aromas are influenced by the winemaker's choices, with oak being the most common influence. Oak imparts nutty, buttery, vanilla and cedar notes to a wine. Malolactic fermentation, a process that softens acidity in a wine by converting malic acid into lactic acid, adds rich, buttery, creamy notes. This process is responsible for the buttery "bouquet" of a Chardonnay, for example.

Aging a wine in lees (dead yeast left over from alcoholic fermentation) imparts bread-like, brioche notes, commonly found in Champagnes. The longer a wine is aged, the more its aromatics will be influenced by tertiary aromas, which include oxidative traits like coffee, caramel, toffee, and cocoa, as well as reductive notes like damp forest floor, mushrooms, or vegetable-like components.

The secondary aromas derived from the winemaking process can be subtle or significant, depending on the techniques employed by the winemaker. These techniques influence the wine's aromatic profile, creating a unique and complex bouquet of scents that contribute to the overall tasting experience.

Tertiary aromas develop as wine ages

Tertiary aromas are the complex components that occur as wine ages, usually in the bottle. They are the result of slow oxidative and reductive processes that alter the primary and secondary aromatic compounds into a harmonious and intricate bouquet.

Tertiary aromas are undoubtedly where the most confusion lies among wine enthusiasts. This is because most wines for sale are meant for immediate consumption, so few drinkers get to experience these qualities. An extended period of bottle ageing is where tertiary notes are born.

In red wines, fresh ripe fruit starts to transform into stewed or dried fruit, like raisins or figs. Tertiary aromas of tobacco, earth and mushroom will also come about. Over time, new notes can appear, such as warm spices, nuts and hints of honey.

White wines start to develop dried apricot, orange marmalade and sometimes even maderized qualities, or sherry-like notes of almonds and candied fruit. Other tertiary characteristics include nutty aromas as well as complex spice components like nutmeg, ginger and petrol.

Bottle age also develops interesting new notes in wines. These may appear over time as "nuttiness, smoke, or honey in whites, and as leather, tobacco, or forest floor in reds", says Dave Rudman, executive director for Wine and Spirits Education Trust (WSET) Americas.

Some wines, such as Rioja Reserva and Chianti Classico Riserva, are intentionally held by wineries to gain bottle age before their release. By the time consumers open them, these wines have already begun the journey from primary to tertiary flavours.

Frequently asked questions