Micro-oxygenation is a delicate process of introducing a controlled amount of oxygen into wine. The mechanical process was developed by Patrick Ducournau in 1991 - he was working with the extremely tannic grape varietal Tannat in Madiran in France. And was looking for a controlled technique to assist in soften the wine for earlier enjoyment. The now known process started being used in commercial winemaking following authorization in 1996 by the European Commission. Today the technique is widely employed across France as well as in several countries around the globe.
The purpose of micro-oxygenation is to bring about controlled desirable changes in a wines palate texture (soften harsh tannins and acidity) and even aroma.

 

The objectives include improved mouth-feel (body and texture), enhanced colour stability, increased oxidative stability, and decreased sharp, unripe fruit aromas. As the process proceeds, one observes an increase of the wines aromatic intensity and palate complexity with a relatively short period of time.
The red wine grape tannins become softer, the body of the wine is increased and a rounder mouth-feel. The exposure of wine to oxygen in limited quantities can be beneficial. Though too much oxygen can lead to oxidation - and too little can lead to reduction and wine faults.
During oak barrel aging, the natural properties of the wood allows for a gentle aeration of the wine to occur over a long period. This aids in the polymerisation of tannins into larger molecules, which are perceived on the palate as softer, smoother in character.
Micro-oxygenation aims to mimic the effects of slow barrel maturation in a shorter period and at a lower cost associated with oak barrels. It also enables more control, as opposed to barely observing it in an oak barrel.
The process of micro-oxygenation involves a large two chamber device with valves interconnected to a tank of oxygen. In the first chamber the oxygen is calibrated to match the volume of the wine. In the second chamber the oxygen is injected into the wine through a porous ceramic stone device located at the bottom of the tank or even barrel.
The dosage is controlled, ranging from 0.75 to 3 cubic cm/ litre of wine. The process normally occurs in multiple treatments during the early stages of fermentation (it also aids in preventing stuck fermentation) - to a more prolonged treatment during maturation.