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Part 3: Aromas From the Winemakers

Now that we’ve seen the important role played by Nature and the luck of the year, let’s take a look at the other important element in the quality of wine: the people behind it.

Around the world, women and men are working very hard to make sure that from the field to the bottle, the potential of their land will be expressed at its best. Whether their job is to grow good grapes, or to harvest them, or to turn them into wine, or to age and bottle the wine or a little bit of all of these, passion is what they all have in common.


Shall we Intervene?

There is a common belief in the winemakers’ world that every time they have to intervene in the process, it will damage the wine. Mother Nature is believed to be the best winemaker ever, and we can only add flaws by trying to improve its work.

However, we can guide it to influence the final style of the wine. The best example of this comes with Sauvignon Blanc. If you taste a Sancerre and a Marlborough Sauvignon Blanc, you’ll go from an austere & minerally wine to a liquid fruit salad, both made of the same grape varietal. Then after that go for Chile and you’ll be halfway between both styles, with the fruity attack of Marlborough followed by a light minerality like the one of Sancerre. So how do they do it? Temperature is the answer! We will go into more details further down. But first, let's visualize most actions the winemakers can take and what their consequences can be.

On the chart, you can see a list of actions that winemakers can make to influence the final taste and style of their wines. Let’s have a look at what they are and how to spot them.


Unripe/Overripe Grapes at Harvest

Because wine is a natural product, there is no exact science to finding the right time for picking the grapes, and it is often down to the grower’s call. Sometimes pushed by the bad weather forecast, they might have to harvest too early with grapes slightly unripe. However sometimes, to develop a wine with jammy, juicy aromas & texture, they might harvest them a bit later, with overripe grapes. So, before we define that, let’s see what we call a “ripe grape”.

During the growing season of the vine, roughly a couple of months after the fruit has set, a period called “Véraison” will start. While the original berries are all green with very high content of malic acid, they will slowly develop sugar, acid, tannins & a whole new mineral composition. This period lasts 1 to 2 months depending on the climate. For instance, grape varietals used for making red wine will develop special phenols in their skin, called anthocyanins, that will replace the green chlorophyll and make the berry turn from green to red/black.

It's actually easy to guess what happens at that stage, think of any fruit you've had that was slightly unripe, how was it? Very acidic and not sweet enough? During the ripening period, sugar levels will also go up by photosynthesis, the levels of acid will decrease, bringing the pH level up (pH is the measurement of acidity, it is made of 14 "points", 0 is the most acidic there is, 7 is neutral and 14 is alcaline, like bleech). Of course a lot of other compounds are developed, with their own influence on aromas and texture. But let’s keep it simple for the moment. A “ripe grape” is a grape that displays the right balance of sugar, acid, tannins & minerals in the winemaker’s opinion. Depending on the style he is willing to produce, he will set these levels differently.

Unripe grapes, by definition, are high in acid and haven’t formed all of their potential sugar yet. Therefore, they will produce high-acid wines with low alcohol levels (sugar becomes alcohol). Some parts of Germany harvest slightly unripe grapes for producing lighter wines (with a low ABV), and it goes the same in the Minho area of Northern Portugal for Vinho Verde, the Txakoli wines of the Basque Country in Northern Spain or some Muscadet in the Loire Valley, France.

The downside of unripe grapes is the “green” aromas they can bring. Examples can be found in poor quality Cabernet Sauvignon, with “asparagus-like”, grassy green aromas.

On the other hand, overripe grapes will sometimes lack a bit of acid and can be very rich in sugar. They produce wines with a high alcohol content and the impact on aromas is shown by jammy, cooked fruits notes (sometimes like a “fruit cake”) and a juicy texture. Many producers in California were chasing this style in their Zinfandel, but they seem to be moving away from that now. It can be found in some Cotes-du-Rhone reds where the heat can generate overripe grapes that lack acidity or in some Garnacha from Spain.


Malolactic Fermentation

This scary word refers to a pretty simple process. The malic acid, naturally found in grapes, is a razor-sharp acid on the sides of your tongue. It is the one you find in Granny Smith apples and pineapple.

After the primary fermentation, the winemaker can introduce lactic acid bacteria into the wine to trigger the transformation of this malic acid into lactic acid. Lactic acid is the acid of dairy products, which adulterates the texture of the wine, leading to a "creamy" or "buttery" mouthfeel (all from dairy).

The malolactic is always made in red wines (acid & tannins don't like each other) but is a winemaker's choice in whites. It can be made totally or partially.


Secondary Fermentation

A bit like what happens in a bottle of craft beer or Champagne, the secondary fermentation, quite obviously, is the one that starts after the primary fermentation (until here, it is quite logical).

The primary or “alcoholic” fermentation is the transformation of the sugars into

alcohol and CO2 by the yeast. When that happens in an open fermenter, the CO2 is released in the air but the alcohol stays in the juice. Naturally, this stops either when there is too much alcohol created in the liquid (that kills the yeast) or when there is no more sugar left. In the latter, winemakers can add a little extra sugar and bottle the wine.

In a closed container like a bottle, the CO2 would have to divide itself into smaller and smaller bubbles and…hey presto: you’ve got sparkling wine! This addition of fizz will give a lighter feel to the wine and completely change its structure. Some sparkling wines, like most Prosecco, undergo both fermentations at the same time in a pressure-tight container. Some others, cheap ones, are a bit like what an industrial lager is to a craft beer, and gas is forced into them. The bubbles are never as elegant and the texture never as refined. If you want to find out more about the magic behind bubbles, click here.


Cold Soaking/Cold Maceration

Mostly used by winemakers for black grape varietals prior to fermentation, it is a way of extracting more flavours and colour. Basically, the grapes are maintained at a low temperature to delay the fermentation process. If some extraction of colour and flavours would also happen during fermentation, it would be along with an extraction of tannins and maybe some astringency. In this case, only flavours and colour are extracted, making wines that are more expressive and deeper in colour, without high tannins.



This time, I am talking about the maceration of grapes during fermentation, when the temperature is slightly higher. Used mostly in reds, it is the moment where the juice gets its colour from the pigments in the skin (anthocyanins), but also where tannins get extracted into the must (that means “juice”). A longer maceration period will lead to harsher tannins and deeper colour in reds (also known as "high concentration").


Temperature of Fermentation

We saw earlier, with Sauvignon Blanc, that the temperature of fermentation could play a big role in the final style of wine. Usually more aromatic elements are extracted during a cooler fermentation while more structural elements (tannins, etc…) are extracted from a warmer fermentation.

Let's get back to Sancerre VS Marlborough Sauvignon Blanc as an example:

  • Sancerre, France, Sauvignon Blanc: To enhance the minerally aromas of the terroir, the grapes are fermented between 16 and 18 Celsius degrees (60.8 to 64.4 Fahrenheit), destroying most of the volatile fruity aromas.

  • Marlborough, New Zealand, Sauvignon Blanc: This more fruit-driven style is produced by fermenting the grapes at a temperature ranging between 5 and 10 Celsius degrees ( that's 41 to 50 degrees for our friends in Fahrenheit) preserving all of the volatile fruity aromas into the wine. Similar techniques are in use in Rueda, Spain, and parts of Italy.


Ageing on the Lees/Autolysis

You might have heard that strange word about Champagne, “autolysis”, what it means is basically “dead yeast cells”. When a wine is aged on its “lees”, that is to say on a bed of dead yeast cells and sediments, it develops a very specific aroma that is close to toasted brioche or bread. Sometimes, it is the case for the infamous Muscadet-sur-Lie (“Muscadet on lees”), a light fizziness might also be created, like a tiny prickle on the tongue.

To increase the contact with the lees and give a richer pastry/dough/biscuit aroma and a rounder texture, winemakers can also do a bit of "Batonnage". The word "baton" means "stick" in French. They take a long stick and stir the wine with it to put the lees back in suspension, maximising the contact.



These two words are contrary to each other. Chaptalization, named after Jean-Antoine Chaptal, is the addition of sugar prior to fermentation in order to increase the alcohol content of the wine. It is forbidden in most AOC areas in Europe, as it only creates alcohol, without the structural elements to sustain it, such as acidity or tannins.

On the other hand, dilution is the addition of water in a must/wine, in order to reduce its potentially high ABV. Again, it often leads to an unbalanced structure and is often prohibited in quality wines. Sometimes, when heavy rainfall hits the vineyard prior to the harvest, it can naturally dilute the grapes. It happened in the late 1990s in Puglia, South of Italy.


High/Low Yields

Spain has the largest area under vines in the World, but it stills ranks 3rd in terms of production. So why is that? Because most of their vines are old and give low yields. It is often seen as a sign of quality wine production, since a vine is a bit like a person: you can do a couple of things really well, or plenty of things poorly.

Some winemakers create low yields by using a method called “green harvest”. When the first fruits set, they cut some of the green bunches and only leave a minimum number of bunches on each vine. This way, the fruit will display a great concentration of aromas and minerals, which should lead to better wines.


Blend of Grapes

Probably one of the eternal debates in winemaking: are single varietal wines better than blends? There is no answer to this question, or in fact, there are too many different answers.

In Bordeaux, reds are traditionally made of a blend of Cabernet Sauvignon, Merlot, Cabernet Franc, Carménère, Malbec & Petit Verdot. Whites are usually made of a blend of Sauvignon Blanc, Sémillon and Muscadelle. In Burgundy, however, reds are 100% Pinot Noir and almost all quality whites are 100% Chardonnay. None of these regions have to prove its high quality anymore, they are both top producing areas.

And you can even push it all the way to Châteauneuf-du-Pape and its 18 grapes allowed in the blend: some black, some white and some even grey.

So, blending grapes together has traditionally been a good way of balancing the weaknesses of a particular varietal with the strength of others. For instance, the GSM blends of the Rhone Valley (which stand for Grenache/Syrah/Mourvèdre) combine the big but short aromas of Syrah with the long-lasting finish of Grenache, for wines that are big from start to finish.

Using different varietals in blends also allows wineries to fight the bad weather conditions they might sometimes encounter. Malbec, for instance, was big in Bordeaux until the terrible winter of 1956. Being a late-ripening grape, most of the crop had been destroyed that year and if Chateaux had only been relying on this varietal for their production, they would have been in trouble. Burgundy, for instance, has had 3 bad vintages in 6 years lately, and some wineries are now facing difficulties since their entire production is based on one white varietal and one black one.


Oak Ageing

Another major player in wine is time. There are different vessels in which wine can be aged, each of them with its different characteristics, but the most iconic of all is certainly the oak cask. Since I already published a full post on the Oak Ageing, I won't bother you with all the details here.

The key things to remember about it are the following:

  • Size of the Oak Cask: From small 40 litre "Blood Tubs" to giant 982 litre "English Tuns", oak casks come in all sizes and shapes. Most winemakers seem to prefer the common Bordeaux barrique (225 litre) for ageing wine. What you can remember is that the smaller the oak cask is, the more powerful oaky aromas it imparts. It is quite logical after all, since the surface of wine in contact with the oak is, in proportion, way bigger in a smaller cask.

  • Age of the Oak Cask: Winemakers can usually choose between a new oak cask and a 2nd, 3rd or 4th use oak cask. In general, the newer the oak cask, the more powerful its aromas. Recently, I met with a Master Sommelier for a training and someone asked "How can you tell, on the nose, if it is aged in new oak casks or used ones?" and his answer was, I thought, pretty amazing: "Well...he said... New oak cask smells like money...". It is true that the high cost of new oak casks naturally leads to premium wines (roughly works out at a cost just under €3 per bottle, only for the oak cask!).

  • The Origin of the Oak: American oak tends to give aromas of vanilla, mocha, caramel & coconut, that are very big from the start but don't last very long. French oak, a different species altogether, gives long-lasting notes of nutmeg, clove & cinnamon. More details are available on the Oak Ageing tutorial.

A lot more tools can be used by winemakers, but we will stop here for today. Don't forget to share the article on your favourite networking site if you liked it! Thanks...


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