You may have already heard this term maturing on lees , or aging on lees or even maturation on lees , in the context of winemaking. But do you know what it is? In this article, we will explain everything to you! What lees are, why we carry out this type of maturation, and which wines are concerned...
What are wine lees?
During the winemaking process, and more precisely during the fermentation phase, you certainly know that yeasts play a fundamental role . Indeed, it is the yeasts which will transform the sugar of the grapes into alcohol , and therefore into wine. Some yeasts are already naturally present in the grapes and others are added by the winemaker.
When all the sugar in the grapes has been consumed by the yeasts, they die and by gravity, fall to the bottom of the vat. This residue of dead yeast then mixes with the grape seeds and fragments of skin or pulp, already present. This deposit formed at the bottom of the vat forms the lees .
The winemaker can then decide to remove the lees from the vat or keep them for the maturation of the wine. If he wishes to remove them, we speak of racking , a phase during which the winemaker removes the residue of dead yeast through the tap at the bottom of the tank. The winemaker can also decide to leave them and age the wine on its lees. And this is where the term aging on lees comes from.
Why age on lees?
Now that we know what wine lees represent and what aging on lees means, you are certainly wondering why. What is the practical purpose of aging on lees?
The lees will give certain properties to the wine . It's chemistry and to put it simply, it's the self-destruction of dead yeast residue, called autolysis, which impacts the taste and characteristics of the wine. Wines aged on lees are regularly stirred in order to release a whole bunch of compounds, particularly mannoproteins, present in the membranes of yeast cells. Composed of sugars (mannose) and proteins, mannoproteins help improve the body of wine . The wine will have a little more roundness and structure . Mannoproteins also help reduce the bitterness of tannins .
There are no rules as to the duration of maturation on the lees , it can last a few weeks, a few months, or even several years. It is the winemaker who chooses the aging time according to the aromas he wishes to give to his wine. Before bottling, the wine is filtered , so as not to disturb the consumer during its tasting.
For which wines?
Many white wines are aged on lees . And all the champagnes without exception, we will talk about them right after!
At Le Chant des Caves, you can find several bottles, from different regions and of different types which are aged on lees. Here are a few. In the South-West, the Pigmentum Gros Manseng , as well as the Pigmentum Ugni Blanc and Colombard , both of the Côtes de Gascogne appellation from Georges Vigouroux and are both aged on lees for several months. We also have L'Aydasse , a Pacherenc from Vic Bihl from Château du Pouey, also made from Gros Manseng, and Petit Manseng. On the Provence side, we find Charmentin , an IGP from Bouches-du-Rhône from Mas de Valériole. The latest example in the Loire Valley, Antoine Van Remoortere raises his two Menetou Salon on lees, both the white and the red .
A must for champagnes!
You understand, for wine, it is a choice of the winegrower, there is no obligation! It's different when it comes to champagne... Indeed, the champagne specifications require winegrowers to age their wines on lees .
Once the assembly is done, the wine is bottled and that is when it becomes effervescent. This is a new fermentation, a draft liquor is added to the wine, composed of still wine, sugar and yeast. Maturation begins, and the lees are still present. The bottles are then stored upside down so that the lees go down towards the neck . They are then removed during the disgorging phase. One of the most common techniques is to immerse the neck of the bottle in a solution at -27°C. The deposit thus finds itself caught in an ice cube, and you will then have to open the bottle to expel them, thanks to the pressure present in the bottle.
Aging on lees being an obligation for champagnes, the specifications also impose a minimum duration. In fact, non-vintage champagnes require at least 15 months of aging, including 12 months on lees. The duration is increased to a minimum of 3 years for vintage champagnes.
At Le Chant des Caves, among our Champagne nuggets, you will find among the De Lozey champagnes, the Cuvée des Gentlemen , aged for 3 years on lees. Or the Cuvée Prestige , aged for 6 years on lees.