MICRO-OXYGENATION electronics-free, making it easy to use, install, adjust, operate and maintain set parameters, even in the event of interruption or sudden changes in the current. modular, allowing for the co-ordination of 2-10 batchers in a single unit. independent oxygen batch setting for each tank. oxygen input through the membrane with very slow, continuous, natural flow (no sudden injections). independent visual inspection of each tank’s membrane candle condition safety signalling device preventing any direct insufflation from cylinder to tank.

Wine can consume most of the oxygen dissolved in it; indeed, it contains no traces of oxygen (Pasteur 1866). Singleton (1987) demonstrated that a light white wine has the capacity to absorb 60 ml/l, and a concentrated red wine up to 600 ml/l - i.e. 10 to 100 times saturation. Our tests show that in 12 days a red wine can consume the oxygen dissolved over 40 consecutive saturations. It has also been seen that O₂ is consumed more rapidly in wines with a high pH. The substrates that mainly take part in oxidation reactions are:

1. - cations of transition metals
2. - polyphenols - some reducing agents
3. - ethanol
4. - sulphur dioxide

O₂ is added to wine in two phases, the first during the period lasting from the end of the primary, alcohol fermentation until the start of the malolactic fermentation; the second period follows on from the malolactic fermentation.

FIRST PERIOD (1): called polymerization: condensation of dry tannins with the free anthocyanins still present.

SECOND PERIOD (2): called harmonization: continuous softening of the tannins and recovery of the colloidal component by means of re-homogenization of the lees.

• the condensation of dry tannins - free anthocyanins by means of ethanol bridges (cetaldehyde) softens the wine overall, condensing the tannins which are not yet completely polymerised with the free anthocyanins still present. The most evident consequence of this O₂-forced condensation is colour stabilisation; another result is the elimination of the harsh, bitter taste which is caused by the tannins resulting above-all from a large number of grape-seeds.
• in this phase the addition of O₂ is controlled on the basis of the evolution of the wine during the previous phase. The most common negative feature during the period preceding bottling is a “closed” taste due to a shortage of correct O2 in the first phase (high reducing strength). Another equally frequent aspect is linked to the unpleasant odours resulting from treatments in the vineyard (sulphur compounds), the evolution of particular aromatic components, and the wine itself.

The period of harmonisation of a wine follows on from its polymerisation phase. Harmonisation takes place in the period following the malolactic fermentation. The most commonly-found problems during this period relate to a lack of colour stability, and above-all problems of odours: “closed”, vegetable and others. Micro-oxygenation applied in the tank contributes to the stabilisation of the colour, helping the condensation of the tannins - free anthocyanins still in the wine, and contributing to the solving of problems involving unpleasant odours.

• an increase in the red colour reading at 520 nm from 3.23 to 3.55
• a reduction in free anthocyanins from 115 to 20
• colour stability with an increase in DTAT from 10% to 65%

A duo-trio tasting test analysis was, of course, carried out on the micro-oxygenated wine in order to find preferences and any differences compared to the untreated wine. Three micro-oxygenated nebbiolos - treated with different doses of O2 - were tasted by a pool of six expert wine-makers, who first achieved 100% matching of the non-treated wines and 95% matching of the treated wines. The most striking result related to the preference test, in which 90% of the tasters placed the three micro-oxygenated wines above the non O2-treated wines, in particular as regards colour and smell. The overall assessment confirmed a 90% preference for the three micro-oxygenated wines.