It’s very difficult, if not impossible, for one single person to thoroughly review every single piece of peer reviewed literature related to wine that is published every day. This Wine Literature Review Lightning Round series presents three new papers (within the past year or two) in one post by briefly summarizing the research and linking to the abstract in order for you to pursue further if you’re interested. If there is enough reader interest, I can review any of the papers introduced to you in this post in a more critical assessment.
VITICULTURE
“Is there a need for leaf-galling grape phylloxera control? Presence and distribution of Dactulosphaira vitifoliae in Swiss vineyards”, published in July 2015 in the International Journal of Pest Management, aimed to evaluate the presence of leaf-galling grape phylloxera in Swiss vineyards, the presence of which has not been previously studied in the primary literature. Specific questions asked were: 1) is the phylloxera present on the leaves and roots?; 2) does the phylloxera prefer varieties with scions or rootstocks?; and 3) are current methods of control appropriate?
![Photo By cathdrwg (Flickr: Phylloxera) [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons](http://www.academicwino.com/wp-content/uploads/2015/09/Grape_leaf_showing_galls_from_Phylloxera_the_academic_wino.jpg)
Photo By cathdrwg (Flickr: Phylloxera) [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons
Brief Results: The results of this study found that phylloxera is present in all wine growing regions of Switzerland. In 80% of the vineyards claimed to be infested with Dactulosphaira vitifoliae, phylloxera were positively identified on the leaves of grapevines. Three locations containing leaf-galling phylloxera also tested positive for the pest in the soil where common rootstock varieties were planted (specifically Kober 5 B and Kober 125 AA), a surprise to the researchers since these varieties are supposed to be phylloxera-tolerant. The researchers concluded their search by saying that the rootstock-scion method for controlling phylloxera is not enough in Swiss vineyards and that more programs need to be adopted in order to prevent greater infection rates and eliminate the pest in the wine growing regions of Switzerland.
ENOLOGY/WINEMAKING
“Chemical and sensory evaluation of wine matured in oak barrel: effect of oak species involved and toasting process”, published in March 2015 in the journal European Food Research and Technology, aimed to evaluate the effect of geographic origin and toasting levels on chemical and sensory characteristics of Merlot wine. Specifically, the researchers focused their efforts on extractible ellagitannins and oak volatile compounds.
Brief Methods: There were two separate experiments performed during this study. The first experiment examined toasting levels, while the second experiment focused on geographic location of the wood used to make the barrels. For the toasting level experiment, the following variables were tested: light toast, medium toast, medium toast with watering, medium plus toast, medium plus toast with watering, medium toast with toasted head, and Noisette. For the geographic location experiment, oak was harvested from the following forest locations: Center, Limousin, Allier, and Colbert forests in France, Pennsylvania forest in the US, and Slavonia forest in Eastern Europe.
Photo by Flickr user Dennis Jarvis (https://www.flickr.com/photos/archer10/15685676486/)
Merlot wines were made and aged for 12 months in barrels using the many treatments listed above and tested for ellagitannins and oak volatile compounds. A sensory analysis (utilizing members of the Oenology Department at the University of Bordeaux, France) was performed on all wines to determine specific sensory characteristics of each treatment.
Brief Results: The results of this study are to be expected: the merlot wines tasted different from one another depending upon which treatment they received. Watering treatment during toasting resulted in increased vanillin and oak lactone extraction. Toasting the head pieces resulted in decreases in eugenol and ellagitannin. Wine made in light toast barrels were described as less sweet, bitter, and more astringent.
In terms of geographic origins, American, French, and Slovanian barrel use resulted in very different wines. The most significant differences between the different wines were in the concentrations of whiskey lactone and eugenol. Wines aged in American oak showed the highest levels of eugenol, followed by French and then Slovania. American oak showed the highest levels of whiskey lactones. Concentrations of ellagitannins in wines aged in Slovanian barrels were about half way in between concentrations in wines aged in American and French barrels. Finally, ellagitannins were significantly and positively correlated with astringency perception in wines.
Based on the results, the researchers determined that barrels made from oak grown in Slovania would be an appropriate source for wine barrels based on the comparable chemical and sensory analyses between those and French and American barrels.
HEALTH
“Arterial compliance may be induced by ingestion of red wine”, published in March 2015 in the Journal of Human Hypertension aimed to evaluate the effect of red wine consumption on blood pressure and arterial compliance (i.e. the ability of the blood vessels to passively expand and contract as needed) in a group of healthy adults. Specifically, they aimed to compare the blood pressure and arterial compliance of healthy volunteers on days they consumed red wine versus days that they did not.
Brief Methods: A total of 18 healthy non-smoking adults (both men and women)
![Photo József Rippl-Rónai [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons](http://www.academicwino.com/wp-content/uploads/2015/09/Father_and_Uncle_József_Rippl-Rónai-red-wine-the-academic-wino.jpg)
Photo József Rippl-Rónai [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons
On the drinking day, subjects drank two 125mL glasses of red wine between 1830 and 0430 hours. Blood pressure and ambulatory arterial compliance measurements were then taken three different times after drinking the wine and at the same times on the non-drinking day: between 1500 and 1830 hours, between 1900 and 0430 hours, and after 0430 hours. Subjects completed various health and demographics-related questionnaires.
Brief Results: The results of this study found that red wine consumption increased heart rate while the subjects were drinking it, and reduced arterial compliance after the wine was consumed. These effects were not seen on the days that the subjects did not drink the wine, indicating that it was the wine itself causing these reactions and not the specific time of day.
Limitations to this study include a very small sample size, and the type of red wine that was consumed by an individual participant was not controlled for. In other words, participants were allowed to drink whatever red wine they wanted, meaning that there could be significant differences between subjects simply based on the type of red wine and not the alcohol alone.