Sweet and sweet wines: how are they made?

But what exactly do they mean? Do you know where the sugar in wines comes from? How are sweet wines made? Explanations.

A matter of vocabulary

First, let's talk about dry wines. Please note that this adjective is not used here to characterize the style of a wine but simply provides information on the level of residual (or final) sugar contained in a bottle. In this case, a dry wine can only contain a maximum of 4g/L of sugar (i.e. 3g for a 75cl bottle). Suffice to say that at this level, it is very generally imperceptible for the taster. A "dry" wine is therefore a wine with little or no residual sugar.

Then come the following categories:

➡️ Demi-sec: between 4g and 12g/L

➡️ Soft: between 12g and 45g/L

➡️ Sweet or sweet: more than 45g/L

A sweet wine is therefore sweeter than a sweet, which is itself sweeter than a demi-sec.

Sweetness scale for still wines

Alcoholic fermentation

Now that these terms are clear, let's now look at how our sugar ends up in the final bottle.

As you know, grapes have sugars in their natural state (like all fruits). Well, apart from the very specific case of chaptalisation, the sugars contained in wines quite simply come from…grapes! Indeed, once the harvest is finished, the winemaker carries out what is called alcoholic fermentation. It is at this moment that the sugar present in the grapes is naturally converted into alcohol by micro-organisms called yeasts. This is when grape juice becomes wine.

The winemaker can then decide either to let the fermentation go to completion (it stops when the yeasts have no more sugar to eat or when the alcohol level reaches around 15% because they cannot survive beyond), or to stop it by its own action so that all the sugar present is not converted into alcohol.

Alcoholic fermentation in progress

For example, in order to make Château Haut-Bergeron Sauternes, alcoholic fermentation comes to an end. However, as the grapes are harvested overripe and have a lot of sugars in their natural state, they are not all converted into alcohol and a large part is therefore still present in the bottle for our greatest pleasure.

On the other hand, natural sweet wines (VDN for those close to you) such as those from Mas Amiel in Maury, Ports such as the delicious 10-year-old Tawny from Quinta da Ervamoira, or the Muscat de Rivesaltes like that of Domaine des Schistes in Roussillon have had their alcoholic fermentation voluntarily stopped by the addition of a wine eau-de-vie bringing the wine above 15% alcohol, thereby killing all the yeasts and therefore leaving the sugar remaining intact.

This addition of alcohol can also take place before fermentation. In this case, all the sugars present in the grapes are preserved. This is the method used for "liqueur wines" such as Macvin from Jura or Pineau des Charentes. To simplify, these are a mixture of grape juice and alcohol.

Finally, other methods such as cooling the wine and filtering it can be used to eliminate yeasts. This is the case, for example, to make the delicious Vouvray demi-sec or mellow from the estate François and Julien Pinon.

Aging in demijohns of a Vin Doux Naturel

The special case of sparkling wines

For sparkling wines (crémants, proseccos, champagnes etc.), another hierarchy exists to qualify the levels of residual sugars:

➡️ Brut nature: between 0 and 3g/L

➡️ Extra brut : between 0 and 6g/L

➡️ Brut : between 0 and 12g/L

➡️ Extra dry : between 12 and 17g/L

➡️ Dry: between 17g and 32g/L.

➡️ Demi-sec: between 32g and 50g/L. The same term being used for wines without bubbles, be careful not to confuse them!

➡️ Mild: more than 50g/L. Same comment as before.

Besides this semantic difference, the sugar in the final bottle of sparkling wines does not come from grapes! Indeed, at the time of the final bottling of a crémant or champagne, the winemaker will add a dosage (or expedition) liqueur to the wine. It is this liqueur made up of wine and cane sugar which, depending on its sugar content, will give our bubbles their Extra Brut, Brut, Demi-sec, etc.

Some domains such as Veuve Fourny & Fils decide to respect the "universe of grapes" as much as possible and choose for their champagnes a dosage liqueur composed of grape sugar! However, this remains a rarity.

Sparkling Wine Sweetness Scale

Conclusion

As you will have understood, if the residual sugar present in sparkling wines comes from an external addition and is very generally cane sugar, for non-sparkling wines, the sugar does come (except chaptalization) from grapes.

Furthermore, semi-dry, sweet or sweet still wines can be made in different ways. Either the wine is made from overripe grapes containing a high level of sugar and its fermentation stops naturally when the alcohol level becomes too high, or the winemaker decides to voluntarily stop this fermentation by its own means (cold and filtration, addition of strong alcohol etc.)

These choices depend on many factors such as the rules of the AOC, the grape variety, the climate or even the wishes of the winemaker.

By way of conclusion, I would advise you to above all pay attention to the notion of balance of the wine tasted rather than the raw number expressing the sugar in it (except for diabetics😉). Indeed, a high sweetness can be perfectly balanced by a beautiful acidity as well as a gourmet aromatic whereas a wine in fact less sweet can seem heavy or even sickening to you if it is not harmoniously built.

See you soon at La Cave Éclairée!