Evaporate your high alcohol

Red wine in glass and Decanter (Photo: Wine republic)

Tired of high-alcohol wines? Like the flavour of them, but sick of being slammed by 15 or 16% alcohol?

The answer is simpler than probably anyone realised. Do nothing.

That’s right. Just pour the wine and let it stand, and wait for some of the alcohol to evaporate.

Pour your wine into a glass or carafe with as wide an opening and as broad a surface-area as possible, and leave it for a couple of hours. The longer, the better. Better still, place the vessel in moving air, such as the draught from an air-conditioner or fan.

New research by a team of Australians has found that alcohol evaporates from wine at a surprising rate.

They found that a red wine of 15.1% alcohol placed in a Riedel Ouverture Magnum glass – the type currently used in many wine show judgings – lost as much as 1.9% of its alcohol (measured as ethanol) in two hours. Placed in a draught, its 15.1% alcohol dropped to 13.2%. Out of the draught, it fell to 14.4%.

The findings were presented to the last Australian Wine Industry Technical Conference by David Wollan, Duc-Truc Pham and Kerry Wilkinson.

The team found that glass shape, headspace and wine volume all contributed to the alcohol evaporation rate. The Riedel glass had the highest ratio of headspace to wine volume of the four glass types used.

Not surprisingly, alcohol evaporation fell to zero when a lid was placed over the glass.

The findings raise some interesting questions for wine tasters, especially in show judging situations. When judges are faced with a large class of wines, say 50, the last wine they taste may have lost a significant amount of alcohol by the time they get to it, compared to the first glass.*

David Wollan is a former winemaker who now works for Memstar, a company that uses reverse osmosis to remove alcohol from wine. Wollan and many other wine professionals now believe wines have what is known as a ‘sweet spot’. The sweet spot is the alcohol strength that gives the best result in the form of tasting pleasure. It’s all to do with balance.

Curiously, it’s not a matter of “less alcohol is better”. It is possible to remove too much alcohol, thus upsetting the balance and diminishing the tasting experience.

When deciding how much alcohol to remove from a certain wine, the technicians prepare several samples of the same wine with slightly varying alcohol concentrations. These are tasted and compared, and the sample which tastes the best will determine how much alcohol is removed from the wine in question.

The disturbing question all of this raises is this: if significant alcohol can be lost by evaporation, thus affecting the sweet spot of wines, how reliable are the results of some tastings?

The issue could easily be resolved by placing lids on glasses.

* In many wine shows, the three judges on a jury often start in different places, eg. one at the first wine, another at the last wine (and work backwards), and the third judge at the half-way point. This may help achieve a good result.

(First published in Gourmet Traveller Wine magazine, August-September 2017)

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