The Further Effects of Global Warming on Wine

Wine is changing dramatically and it may not be for the better it also may not be the fault of the winemakers and vintners. The problem lies with global warming. Whether a natural cycle of the Earth or induced by man, there is no doubting that a major change in our climate condition is occurring.

While the effects of this warming are not yet devastating or even terribly obvious, the effects are beginning to show up in some of the wines you drink by an increase in alcohol levels.

Wine grapes cannot be grown just anyplace; it takes a whole series of natural conditions as well as some intervention by man to produce the quality fruit required for wine. Most grape growers and winemakers know this to be a fact and have searched out perfect places in the world where topography, soil, and climate come together to produce quality grapes and thus good wine. A vineyard should be located on low sloping hills with well drained soil. There must be adequate sunshine and rainfall and most important, the climate must not be to hot or too cold.

Centuries ago, in France, the birthplace of modern wine, it was discovered exactly where to place a vineyard to get the best grapes of a specific variety by the simple hit and miss method. There are places in France where a great vineyard is just across a narrow road from a poor or mediocre one. In Northern California there are large areas where all of the factors are in place on a massive scale and it is almost impossible to grow inferior grapes.

It is in the realm of climate where the global warming comes in. Areas that were formally cold are warming up. Areas which were warm, but adequate for grape growing, are becoming too hot for the vine to produce well. This is not as impossible as it sounds. The past few vintages in Southern Italy and Greece have been the worse in memory and scientist are convinced that the cause is global warming.

All of this is not as bad as it seems. What has resulted from global warming in California is a remarkable decrease in the spring frosts which slows the flowering of vines and thus eliminate the all too often springtime frost damage. This allows a longer time for the grapes to ripen, usually a very positive occurrence as the additional summer heat stimulates the vines to grow and produce large crops of sweet grapes. All in all, both these events should have resulted in better grapes and as a corollary, better wines. Unfortunately there is a dark side to all of this.

The dark side is quite simply put; an increase in the alcohol level of the wines. When the weather is too hot, and there is enough sunlight, grapes produce more natural sugars. It is these natural sugars that yeast turns into alcohol during the process of fermentation. One of the beauties of wine is that its production is a totally natural process.

To make a dry wine the winemakers allow the yeast to do its job until there is no more sugar to convert to alcohol and the yeast dies. Is a picture starting to emerge? The more sugar the grape develops, the higher the alcohol level. To make sweet wines, the yeast is killed part way through the fermentation process by chilling or as in the case of Port wine, adding brandy. The problem is that there is no effective way to reduce the alcohol level of a wine after it has been made without considerable intervention by man and thus, most probably, in some way, changing the quality of the wine.

The reason for this long winded tirade is to inform readers of the problem and caution them to check the alcohol levels of the wines they buy, regardless of price. If there is a significant increase, or you feel that it is too high, approach with caution.