What is controlled oxygenation?
Historically, controlled oxygenation, i.e. the gentle, slow addition of oxygen, is not a new concept in wine. In fact, it's the oldest, since for centuries wine has been vinified, aged and preserved in containers that are more or less permeable to oxygen. Containers such as amphorae are making a comeback, symbolizing these traditional practices. However, this controlled supply of oxygen, while beneficial to the wine, was not controlled.
From the 1960s onwards, with the development of oenology, wines were stored in inert containers, solving the problem of microbial contamination. The widespread use of this type of tank, combined with improved hygiene, enabled the elimination of many defects, but also meant that the controlled oxygenation that occurred naturally in barrels came to a halt.
Nearly thirty years later, Patrick Ducournau, winemaker from Madiran and founder of Vivelys, while training in Burgundy, began to wonder about the impact of barrel ageing on the profile of wines, and in particular the role of oxygen. He noticed that Pinot Noir, a " sensitive " grape variety, underwent a positive metamorphosis on contact with oxygen. In particular, he noticed that wines that had not been able to undergo malolactic fermentation in autumn, and had been left to settle in barrels throughout the winter, showed more color, fullness and roundness of tannins on the palate than other wines.
Later, during vinification, he also noticed that the tannat from his region of origin sometimes needed more oxygen than the barrel could provide. He then had the idea of inventing a tool that would deliver oxygen repeatedly and at the required dose, i.e., that would reproduce the oxygen delivered by the barrel, but in a way that could be adjusted according to the wine's needs. The concept of micro-oxygenation was born.
The birth of micro-oxygenation
Les premiers travaux sur la micro-oxygénation ont démarré juste après et ont abouti au dépôt d’un brevet en 199Very logically, the dissolved oxygen concentration in an inert vat during ageing is close to 0 mg/l.
On the other hand, as the barrel is an oxygen-permeable tool, the dissolved oxygen concentration during ageing is also close to 0 mg/l. In this container, oxygen is added at a sufficiently slow rate to give the wine time to consume all the oxygen provided, without it accumulating in dissolved form. During racking, on the other hand, in vats or barrels, the dissolved oxygen concentration can be very high (several mg/l).
Controlled oxygenation is therefore characterized by a supply of oxygen at a rate lower than the rate of consumption by the wine, and therefore a dissolved oxygen concentration close to zero. This is what differentiates it from punctual oxygenation, and what lies at the heart of the micro-oxygenation technique.
Two types of oxygenation can also be distinguished by the very different effects they produce:
- for the same total quantity of oxygen, moderate oxygenation favors color stabilization, the degradation of vegetal characteristics and the disappearance of reduced tastes, while increasing the wine's reductive power;
- violent oxygenation favors oxidation and aging.