What was done
In the words of the authors, "the impact of elevated carbon dioxide concentration on the quality of berries, must, and red wine (with special reference to volatile composition, phenolic content, and antioxidant activity) made from Touriga Franca, a native grape variety of Vitis vinifera L. for Port and Douro wine manufacturing grown in the Demarcated Region of Douro [northern Portugal], was investigated during 2005 and 2006," in which study grapevines were grown in open-top chambers maintained at either 365 or 550 ppm CO2.

What was learned
The six Portuguese researchers report that, "in general, the increase of CO2 did not affect berry characteristics," and "did not significantly change the total antioxidant capacity of the red wines." In fact, they say that "thirty-five volatile compounds belonging to seven chemical groups were identified," and that, "generally, the same volatile compounds were present in all of the wines." Although some of these compounds were "slightly affected," they say "the red wine quality remained almost unaffected."

What it means
Goncalves et al. say their study showed that "the predicted rise in CO2 might strongly stimulate grapevine photosynthesis and yield (data not shown) without causing negative impacts on the quality of grapes and red wine." And putting their personal stamp of approval on their findings, they add that "the informal sensorial analysis carried out by the researchers" also showed that "wine quality remained almost unaffected." Oh, what some will not do for science!