micro oxydation may04

ten years micro oxygenation experience in USA

Blackburn, D. (2004, March/April). Micro-Oxygenation. Lessons from a decade of experience. Practical Winery Vineyard, pp. 32-38.

Micro-oxygenation has been used in a number of wineries in the US for the last 10 years.

This paper looks at the history, the rationale and discusses the principles behind using micro-oxygenation.

In traditional vinification wines are regularly racked and in the process low levels of oxygen incorporated.

The process of micro-oxygenation was initially developed by French oenologist/innovator Patrick Ducournau as a means of taming the tannins in big red wines from southern France.

The aims of micro-oxygenation are to:

improve the conditions leading to the polymerisation of the tannins resulting in superior mouth feel
eliminate sulphides
integrate herbaceous aromas.

The quantity of oxygen to add to wines varies from wine to wine. Considerable experience is required to optimise oxygen additions. Addition rates range from initial levels of 50 to 60 mL/L/mo (millilitres per litre per month) down to an ultimate level of 1 mL/L/mo.

Three key lessons learnt:

not all wines benefit from micro-oxygenation with low tannin wines such as Pinot Noir requiring very little additional oxygen if any.
micro-oxygenation is an ongoing process coexisting with several stages in the wine's early life. The treatment should be commenced as the wine goes dry. Initial levels could be of the order of 50 to 60 mL/L/mo. The oxygen added should be consumed entirely and there should be no increase in dissolved oxygen. Additions should continue throughout the malolactic fermentation. Following malolactic fermentation sulphur dioxide is routinely added. Oxygen additions at this stage should be reduced to around 1 mL/L/mo. If excessive levels of oxygen are added post sulphur dioxide addition the free sulphur dioxide level will drop.
there are two schools of thought regarding went to begin micro-oxygenation the first at the completion of the primary fermentation and the second not until the malolactic fermentation has finished. Most people opt for the former.

When micro-oxygenation is started during malolactic fermentation low levels of acetaldehyde are formed and these are important in the polymerisation process. This acetaldehyde is normally metabolised by the malolactic bacteria.

Micro-oxygenation is a continuous process with the oxygen being consumed by the wine and there being no increase in dissolved oxygen.

To obtain the maximum benefit from micro-oxygenation the winemaker needs to be diligent in tasting wines every day or two and in testing dissolved oxygen twice a week.

Proponents of the technique claim that micro-oxygenation will lead to increased quality, reduced oak costs and reduced cellar labour costs through less racking and handling of wine.