The move by the OIV comes amid a rise in the popularity of low-alcohol wines, with producers such as Skinnygirl targeting female consumers in particular. Other winemakers are seeking to reduce the high alcohol content of their more potent wines, created by factors such as better vineyard management and the picking of grapes later (and riper). Some can have alcohol levels of up to 17 percent. Alcohol reduction can also improve the taste balance of particular wines.

Alcohol is reduced or removed using techniques such as spinning cones and reverse osmosis. Conetech, a California-based company which specializes in "alcohol adjustment," says it treats six million gallons of wine annually from around 600 clients. It also has plants in Chile, Spain, France and South Africa, with Australia soon to follow.

The difficulty is that the rules governing the use of alcohol-reduction technology vary worldwide. It's permitted in the United States, for example, but the rules in Europe are less liberal. In addition, some countries have not yet tapped into the low-alcohol trend.

To counter this confusion, the general assembly of the OIV has adopted four resolutions to address "both the expectations of the vinicultural sector and a growing appetite of consumers for low-alcohol or directly dealcoholised beverages of viti-vinicultural origin." They are designed as recommendations to the organization's members, which include wine-producing countries such as Australia, Argentina and European Union member states. The United States will not be affected, as it does not belong to the OIV.

Meeting in the Turkish city of Izmir, the general assembly announced that its International Code of Oenological Practices would, for the first time, include official definitions of the treated wines, as well as specifying the separation techniques that could be used.

"Correcting the alcohol content of a particular wine, which means to reduce an envisaged excessive level of ethanol to improve its taste balance, is allowed with a maximum reduction of 20% [of the original alcohol level]," said the OIV. "Products obtained through this practice must still conform to the definition of wine, and especially keep the minimum alcoholic strength of wines, if they are to be presented as such."

The organization's "definition of wine" states that: "Wine is the beverage resulting exclusively from the partial or complete alcoholic fermentation of fresh grapes, whether crushed or not, or of grape must. Its actual alcohol content shall not be less than 8.5% vol." (This minimum may be reduced to 7 percent in certain regions.)

In Britain, Sovio Wines lost a High Court battle to overturn a ban imposed on its Spanish imports. Spinning cones had been used to reduce the wines' alcohol levels by 40 to 50 percent, taking their alcohol level to below 8.5 percent.

According to the OIV's new resolution: "If the alcohol content of the wine is reduced by more than 20 percent, it will fall under a dealcoholisation process ... the resulting product shall not be presented [solely] as wine, since it will not comply with the established definition."

Products with an alcohol content of between 0.5 and 8.5 percent will be defined as "having been obtained by partial dealcoholisation," while those below 0.5 per cent are defined as "dealcoholised."

The OIV said the permitted "separative techniques" were: partial vacuum evaporation (the process used in spinning cones), membrane techniques (which include reverse osmosis) and distillation.

The organization is currently working on definitions for wines that have "gone through an alcohol reduction of more than 20% but do still respect the minimum alcohol level for wine and special wine."