May 3, 2010

Red Wine Story

Filed under: Agriculture

Close your eyes. You are sitting by a fireplace, you’ve just open a bottle of vintage Port wine your friend brought back from Portugal, you’ve cracked open Al Gore’s latest book … ouch, things were actually going pretty well with the fireplace and the vintage Port!

We bring this up given some really good news for Port lovers that appeared recently in the Journal of Agricultural and Food Chemistry. We realize you’ve probably read this piece already given the widespread circulation of the journal and the intense media coverage of the article? No?! Then we’ll fill you in.


WOW – looks good for sure!

Some wine lovers would die on a cross defending their opinion that the best Port wines in the world come from the Douro region of Portugal (see Figure 1). Geography came together there to give the near perfect climate and soils needed to grow grapes wonderfully-suited for Port wine.


Figure 1. Douro region of Portugal

Folks in the area have been at this for a long while—there is archaeological evidence for winemaking in the region dating from the end of the Western Roman Empire during the 3rd and 4th centuries. Winemaking flourished during the Medieval times from the mid-12th century (we hate to bring this up, but this was a particularly warm period), and then in the 17th century, the region’s vineyards expanded, and the earliest known mention of “Port wine” dates from 1675 (things seemed to be doing well in the Little Ice Age Period as well). As part of the regulation of the production and trade of this valuable commodity, a royal Portuguese charter of 10 September 1756 defined the production region for Port wine (again, this occurred during a relatively cold period). It thus became the world’s first wine region to have a formal demarcation. The Douro winemaking region was declared a World Heritage Site World in 2001—a visit is highly recommended!

The research of interest here was produced by six scientists with Portugal’s University of
Trás-os-Montes e Alto Douro (sounds like a great place). Gonçalves et al. begin their article stating:

Carbon dioxide (CO2) is the most important greenhouse gas, and its concentration has been increasing since the beginning of the industrial revolution, mainly as a result of the burning of fossil fuels. Compared with preindustrial levels, the CO2 concentration ([CO2]) has increased by 34%, with an accelerated rise since 1950. If no climate-driven policy measures are implemented, it is expected that CO2 will exceed 550 ppm by the middle of the 21st century. The continued increases in CO2 and other greenhouse gases in the atmosphere are expected to induce an additional 1-4.0 ºC increase in average global surface temperatures by the year 2100, leading to the scenario of future higher evaporative demand and increase in drought frequency and intensity. The predicted changes in [CO2] are expected to increase C3 plant carbon assimilation and, therefore, increase growth rate and yield of plants.

If you have forgotten you basic biology lessons, C3 plants dominate temperate zones and certainly include grapevines grown in mid-latitude locales.

The researchers go on to note that:

During the past two decades, epidemiological studies have shown that coronary heart diseases are less prevalent in countries where a regular and moderate consumption of wine is widespread. Particularly, red wine is an important source of polyphenols, which are capable of inhibiting the processes behind coronary artery disease. In addition, red wine effects include inhibition of chronic inflammation and thrombotic tendencies. The inhibition of human low-density lipoproteins (LDL) in vitro was demonstrated by the addition of the mixture of polyphenols from wine. It has recently been revealed that the consumption of wine by humans leads to an increase in the antioxidant capacity of plasma. Red wine produced in the Demarcated Douro Region is one of the most important products in the Portuguese economy.

We get the message—red wine is good for humans and good for the economy of Portugal.

For this experiment, the team selected “Touriga Franca, a native grape variety of Vitis vinifera L. for Port and Douro wine manufacturing grown in the Demarcated Region of Douro.” The Touriga Franca is widely regarded as one of the top, if not the top, variety of grapes used to produce Portugal’s leading Port wines. During 2005 and 2006, “Grapevines were grown either in open-top chambers (OTC) with ambient (365 ± 10 ppm) or elevated (500 ± 16 ppm) [CO2] or in an outside plot.” We see hundreds of articles regarding the effects of elevated carbon dioxide levels, and we can certainly appreciate the value of focusing on grapes used to produce the world’s finest Port wines! Soy beans just seem boring in this regard.

There were many interesting findings from this study. One statement in their article caught our eye as they report “Wines produced in elevated [CO2] in 2005 had considerably (P < 0.01) higher alcohol and lower pH than wines in ambient [CO2].” The alcohol level in 2005 was 12.1% for the elevated CO2 plants and 10.9% for the ambient plants – wine lovers would enjoy a 10+% increase in alcohol content thanks to elevated CO2. Higher alcohol level sounds good to us. For whatever reason, there was no increase in alcohol noted in 2006 (OK, so we get an average increase of 5%—who’s complaining?) Perhaps more important, they note that “In summary, this study showed that the predicted rise in [CO2] might strongly stimulate grapevine photosynthesis and yield without causing negative impacts on the quality of grapes and red wine. In fact, our data based on the analyses of wine following fermentation and the informal sensorial analysis carried out by the researchers showed that, although some of the compounds were slightly affected by elevated [CO2], wine quality remained almost unaffected.” Sign us up for this research!

So with elevated atmospheric carbon dioxide levels, we can get generally higher alcohol content, more yield of grapes, and no decline in wine quality? Skip cap and trade—we see nothing but a better world with the benefits on higher levels of CO2.

Reference:

Gonçalves, B., V. Falco, J. Moutinho-Pereira, E. Bacelar, F. Peixoto, and C. Correia. 2009. Effects of elevated CO2 on grapevine (Vitis vinifera L.): Volatile composition, phenolic content, and in vitro antioxidant activity of red wine. Journal of Agricultural and Food Chemistry, 57, 265-273.




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