American Wine Society Educational Foundation Scholarship Winner Talks Sour Grapes
By David Edwards, Chapter Cahir, Glimmerglass Chapter AWS
The Glimmerglass Chapter of the American Wine Society in Cooperstown, New York, recently hosted Megan Hall, Ph. D. candidate at Cornell (Go Big Red !) University and winner of a 2015 —2016 AWS Foundation scholarship. Prior to the scheduled Garnacha tasting Megan described her path to plant pathology and her current research on the etiology and treatment of sour rot, one of those little understood grape diseases that can ruin a crop in the last few weeks of the season.
Megan spends most of her time at Cornell’s Agricultural Experimentation Station at Geneva on the northern end of Seneca Lake or, as she prefers, in the vineyards of various Finger Lakes growers.
Although it is a well-recognized disease, very little research has been done on sour rot. Megan has found that as grape sugars increase, the berry skin is penetrated—maybe insects, maybe birds, maybe hail, maybe simply swollen berries from excessive rain. In any case, natural occurring yeasts on the berries enter the fruit and begin to ferment the sugars inside the berry, producing alcohol. The fermentation then changes to an Acetobacter fermentation, yielding acetic acid (vinegar, or ‘sour wine’), hence, “sour rot”. Fruit flies are observed, and are probably involved as a source of the Acetobacter.
The symptoms of sour rot —they occur just a few weeks before harvest—are mushy berries, a loss of color in the skins and a distinctive odor of vinegar throughout the vineyard even when the disease is limited. Thin skinned varieties and tight bunched varieties appear to be the most susceptible.
After determining the disease pattern, Megan is now in the process of developing treatments, focusing on environmentally safe sprays and the proper timing of what will hopefully be a single spray.
After her presentation Megan was assailed with questions from Chapter members, questions she handled with aplomb.
Based on this presentation, the scientific approach used, the practical application of the research and the obvious enthusiasm of the researcher, the AWS Foundation made an excellent selection of this scholarship winner (she has won twice, by the way). However, as with most plant pathologists, Megan’s definition of a “good season” is diametrically opposed to the views of growers—she prefers a season full of diseases that can be evaluated, researched, documented, and treated, with the goal of developing ways for growers to have a good crop in any vintage.
Megan, who studies under Wayne Wilcox, Ph.D., Professor and Associate Chair of the Department of Plant Pathology and Plant-Microbe Biology at Cornell, will be spending the Spring semester continuing her research in South America, where it will be growing and harvesting season.
Megan was recently honored by the American Society for Enology and Viticulture-Eastern Section, for the best student paper of 2015 which dealt, of course, with sour rot.
In appreciation, the Chapter presented Megan with a selection of local products—Ommegang Brewery’s ‘Three Philosophers’ Ale (appropriate for a Doctor of Philosophy candidate), Fly Creek Cider Mill Hard Cider, Honey from the free-range bees of Murphy Hill and some home-made wine.
Other Chapters with an AWSEF scholarship winner within driving distance should consider the unique opportunity that this offers and invite the student to speak with the Chapter.