What you need to know about wine flavours

What are wine flavours? How do we perceive them? Where do they come from? Learn how to classify, identify and talk about wine flavours. Without snobbery… But with infographic!

The kaleidoscope of marvellous flavours that can be discerned in wine is the main reason I first entered this fantastic and complex world. It simply astonished me that a glass of liquid could contain such a great variety of different nuances. For me, it was (and still is) like magic. Since the first time I approached wine, I have had a need to make sense out of the unfurling flavours, studying what creates them and how we can talk about them. 

This article is part of my ongoing attempt to illustrate the dimensions that characterise our beloved fermented grapes. By doing this, we can successfully recognise and discuss wines’ intricacies.

On a very broad level there are two main things that define wine:

• A set of structural components (sweetness, acidity, alcohol, tannins, body) that makes up the “architecture” of a wine
• The flavours that adorn the wine’s underlying structure

I treated the structural components of wine in two of my previous articles (Part 1: Sweetness and acidity and Part 2: Alcohol, tannins and body). In this article I will focus on wine flavours. My purpose is to allow my readers to make sense of the flavours in wine. To understand what these flavours are, how they originate and how we can categorise them. Ideally adding another piece to the puzzle in solving the mystery of the most fascinating beverage of earth. Before we start on flavours, let’s go into a bit of biology and chemistry.

The chemistry of flavours

From a chemical perspective, flavours are the manifestation of compounds called stereoisomers that are released at different stages during the wine life cycle. In this regard, smell (as taste) is a chemical sense, meaning it’s stimulated by chemical compounds that travel from food, liquids and other substances.

When we smell these compounds, a stimulus is transmitted to our brain that compares it to a “memory” of known sensations – eventually conjuring a final impression. For example, while smelling a wine rich in pyrazines you might identify blackcurrant leaves or bell pepper. Of course, this is not because your drink contains an amount of that green substances; for your brain, those aromas are the closest known things that smell like pyrazines.

If you were attentive, you probably noticed that I only mentioned the sense of smell. That’s correct. In our journey in the land of flavours, smell is our only companion. Not taste. 

This might sound counterintuitive since we feel flavours when savouring wine in our mouth (and wine tasting notes rightfully include aroma descriptors when referring to the palate). Still, our sense of smell is the only way we are capable of perceiving flavours.

The confusion probably arises because we have two ways to sense smells or, to be more precise, olfactory functions. The most obvious way we perceive smells is the orthonasal olfaction. This occurs when we sniff something – using our nostrils to capture scents. The other way is the retronasal olfaction which takes place when aromas are detected via our oral cavity, using the retronasal pathway, located behind the mouth at the back of the throat.  On a side note, the two functions operate in a slightly different way. When the wine reaches the mouth, our body warms the liquid which brings out the less volatile compounds in the aromatic profile.

In both circumstances, the scents arrive at our olfactory receptors located in the nasal cavity. These receptors detect stimuli and pass the relevant information to the olfactory bulb, the part of the brain dedicated to the sense of smell. The brain decodes the data and casts around its memory banks for a final interpretation of the thing smelled.

Flavour classification

Aside from chemistry and anatomy considerations, how we can classify flavours?

In the wine world, people usually categorise them in three macro categories: primary, secondary and tertiary.

Primary flavours

Primary flavours originate from the grape and the surrounding environment (yeasts also play a significant role) and these develop during fermentation. The last addendum is important. If you pick some grape berries from the vineyard and smell them, for sure you won’t sense any of the captivating descriptors you read in tasting notes. This is because it is the fermentation process (with all the interesting things this includes) which is the real catalyst and extractor of flavours.

Primary flavours fall in a few clusters, each containing an array of similar (and more specific) nuances:

• Fruit: this is probably the most common and numerous of the clusters; it can be grouped into a few sub-clusters:
  • Citrus fruit: lemon (juice, peel or zest), lime, grapefruit, orange
  • Orchard fruit: apple (red / green / yellow), pear, quince
  • Stone fruit: apricot, nectarine, peach
  • Tropical fruit: mango, pineapple, passion fruit, kiwi, banana
  • Red fruit: strawberry, raspberry, currant, red cherry, red plum
  • Black fruit: black cherry, blackberry, black currant, blueberry, black plum
  • Resinated/dried fruit: prunes, sultanas, raisins, fig
• Floral: rose, violet, peony, geranium, primrose, honeysuckle, acacia, lemon blossom, jasmine, iris
• Vegetal: grass, fern, fennel, anise, liquorice, green tea, nettle, gooseberry, black currant leaves, bell pepper
• Mineral: wet stone, iodine, chalk, gunflint, slate
• Spices: black or white pepper, garrigue, thyme, rosemary, bay, juniper

The above clusters (and aromas) are not set in stone. There is no classification that is better or preferable. Nonetheless, I do encourage wine lovers to think about flavours in terms of clusters and sub-clusters, before delving into the more specific aromas. I personally found this approach very useful in identifying flavours. Taste a wine and go through the clusters and try to determine which ones are present. Once you’ve identified the clusters, be more selective and try to identify the specific aromas. This approach is valid for all aroma clusters, not just the ones for primary flavours.

Secondary flavours

Contrary to primary aromas, secondary flavours are bestowed by a winemaking practice rather than by mother nature. The main three vinification techniques that confer secondary flavours are the following:

• Oak usage: imparting notes of vanilla, cloves, nutmeg, cinnamon, toast, chocolate, cedar, roasted wood. There are several influencing factors here: the size of the barrels, new vs old oak (the newer the oak, the stronger the flavour), American vs European (the former has a sweeter influence – vanilla, coconut mostly – whereas the second is more toasty and savoury)
• Malolactic fermentation: this process happens during or after fermentation and it transforms the tart malic acid into the more mellow and soft lactic acid. When malolactic fermentation takes place for white wine, it gives buttery and dairy flavours (butter, cream, soft cheese, yoghurt); New World chardonnay usually undergoes this process and exhibits these kinds of scents
• Lees contact: lees are the deposit of dead yeasts that remain after the completion of alcoholic fermentation. Prolonged contact with lees imparts biscuity flavours to wine (brioche, bread dough, biscuits). Champagne is a notable example where this happens

Tertiary flavours

Tertiary flavours are solely ascribed to age. Wine can age in two different ways:

• Oxidatively: mainly in oak barrels – these are not airtight and therefore allow controlled quantities of air to come in contact with wine. Aromas of coffee, toffee, caramel, walnuts, nuts develop this way
• Anaerobically: developing with bottle ageing, tertiary flavours in this case include: honey, petrol, mushroom, marzipan, leather, earth, wet leaves, meat, tobacco, resinated or dried fruit

It’s worth noting that the same flavour can be attributed to more than one of the categories above and the exact reason can vary from case to case, based on the nature of a particular grape variety or the winemaking procedures adopted. For example, resinated and cooked aromas (prunes, sultana, figs) can either be tertiary flavours from bottle age or primary aromas in wines from warm regions, where the fruit is so ripe as to become jammy (for example in grapes such as zinfandel, primitivo, pinotage or some New World shiraz).

The development of wine

The presence or absence of different categories of flavours is typically used to describe the state of development of a particular wine. With a degree of simplification:

• A youthful wine is one where primary and secondary flavours dominate; there are no tertiary flavours
• In a developing wine the primary and secondary flavours are prevalent, but some tertiary aromas have started to emerge; a 6-7 year-old red Bordeaux is a perfect example
• A wine is described as fully developed when the predominant aromas are tertiary. Primary and secondary flavours can still be present, but they are not prevalent
• A wine is called tired when it has passed its best state: the wine has deteriorated and its aromas have faded and are no longer attractive 

Whereas quality wines follow a natural progression throughout these states, it’s important to understand that not all wines benefit from age. In fact, most wines don’t age well and are meant to be consumed rapidly upon release. These wines just proceed from youthful to tired. They lack the structure and the flavour intensity to positively evolve over time.

Prevalence of a flavour type

Another aspect worth stressing is that a wine does not need to have flavours in all three categories (primary, secondary, tertiary) to be considered good. Some wines, either due to their particular style or the vigneron’s vision, may lack an entire category of flavours. That would not automatically detract from the overall quality of the end product. 

For example, wines made from sauvignon blanc (at least in its two most classical declinations: Loire Sauvignons and Marlborough ones) are famous for being fresh, racy and intensely aromatic. Consequently, they only exhibit primary flavours. They lack secondary and tertiary flavours would cover the inherent aromatic intensity coming from the grape. Similarly, it’s perfectly plausible for a winemaker to want to create a wine focused merely on its pure fruitiness. Think about traditional prosecco for instance. In this case, the vinification procedure will be adapted accordingly (for example, no use of oak at any stage, preferring inert vessels for fermentation and maturation). Again, we will only have primary flavours. Nonetheless, we can still experience, if the product is well crafted, a wonderful wine. On the other hand, in some wines secondary and tertiary flavours dominate and primary aromas are virtually missing. Take Sherry for example (I wrote a mini-series about Sherry that you can read here). The typical flavours of these wines, either the snappy tanginess of a fino or the rich nuttiness of an oloroso, are entirely down to the winemaking process. The quality of Sherry is not determined by the presence or relevance of primary flavours. 

Flavour description

A final note on the use (or abuse) of fanciful descriptors. It’s perfectly acceptable to strive to use a nuanced vocabulary to express the different subtleties of the amazing effusions coming from the glass. But we should bear in mind that the main goal of wine tasting notes and wine writings in general is successfully communicate among wine passionates. In my humble opinion, trying too hard to impress people or to act snobby is not useful to anyone.

My advice when talking about a wine is to make an emphatic effort to use descriptors/words which are easily understood between the producer and the consumers of the message. Choice of words should be relatable and shareable. As an example: 

Hints of liquid boysenberry, Don Cherry and Frankenberry flourishes

Needs to be re-written in:

Hints of raspberry and crunchy strawberry with a decent ripeness of flavours

In other words, if your reader or listener has to perform three Google searches (like I did!) to understand what you’re talking about, perhaps something has gone wrong.

Final thoughts

Smell is definitely the most mistreated of our senses. For a long time we thought humans were rather deficient at recognising scents (recent studies have demonstrated the opposite). 

Nonetheless, wine lovers are enthused by the realm of aromas. Tasting notes are scattered with aromatic descriptors. You can see connoisseurs attentively sniffing their glasses in search of hidden nuances. What’s all the fuss about flavours? I hope this article helped to answer that question.