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Five Questions for Hans Walter-Peterson

by Chris Gerling and Hans Walter-Peterson


Hans Walter-Peterson first joined Cornell Cooperative Extension in September 2001 as the viticulture extension specialist with the Lake Erie Regional Grape Program. In 2007, he moved to the Finger Lakes region where he is the viticulture extension specialist and leader of the Finger Lakes Grape Program. He received his bachelor’s degree in biology from St. Olaf College in Minnesota (Um Ya Ya!), and his master’s in viticulture from the University of California at Davis (and he has no idea what their fight song is).


What inspired you to work with grapes?
Thanks to a fantastic professor, I was very interested in plant physiology during my undergraduate program. Unfortunately, I had no idea what I wanted to do in biology after graduation, so I jumped into a few different jobs before ending up as an environmental planner in Minnesota. I started to learn about wine as a hobby with my father and a few friends. One day, it dawned on me that my interest in plant biology and my enjoyment of wine actually intersected and that I could consider going into viticulture as a new career. After working some part-time jobs at a wine shop and a small vineyard in Minnesota, I realized viticulture was a subject where a lot of my interests came together.  I applied and was accepted to the graduate program at UC-Davis where I got the chance to study with Andy Walker, Nick Dokoozlian and a number of other great faculty.

What are the major challenges in your field?
From a grape growing perspective, I think the biggest challenges we still face in the Finger Lakes, and in eastern North America in general, all come back to water. Whether it’s too much in the soil leading to excessive vigor, too little in the soil causing drought stress, or too much in the atmosphere leading to higher disease pressure during the season, the impacts of precipitation and relatively high humidity on grape growing in this climate are huge. California, eastern Washington and other ‘Mediterranean’ climates where rainfall is limited during the season have a big advantage over the East in this particular realm.

What is your vision for your position within the E & V program?
I see one of my primary responsibilities in the program as being the link between the Finger Lakes grape growers and Cornell. We have a wealth of great information on viticulture & enology here, but the industry can’t benefit from it if that information doesn’t get out to them in a ways that enable them to incorporate it into their operations. It is our job to sift through all of the research done at Cornell and other universities and pick out the “nuggets” that will help growers to address the challenges that they are facing in their vineyards.

What projects are going on in your program right now?
We are in the process of wrapping up a project looking at the impacts of late-season fungicide applications on fermentation and sensory characteristics in Cabernet Franc. It’s an unfortunate fact that growers sometimes need to apply fungicides fairly close to harvest in some years to control botrytis or downy mildew until the fruit is picked. Winemakers, however, are understandably wary about any chemical applications close to harvest that could affect the final wines made from those grapes. Our project harvested fruit just at the end of the pre-harvest interval (PHI) for several fungicides that could be used near the end of the season, fermented them, and then ran them through sensory tests. Our preliminary results seem to indicate that there is no consistent impact on the wines made from fruit with fungicides applied just before harvest, but we won’t draw any conclusions until we have finished the trial.

We are also just starting a Riesling clonal trial in cooperation with a local vineyard, in order give growers and wineries better information about how different clones perform in the vineyard and in the winery. This project is also exciting for me because it will be the basis for my Ph.D. research.

What project would you pursue, if funding was unlimited?
I would love to work on a long-term, comprehensive study looking at the potential for growing Riesling in New York using a totally mechanized system for vineyard management – pruning, shoot thinning, leaf pulling, shoot positioning, fruit thinning – the works.  Why would I want to do this? Economics. If we could produce relatively high tonnage for a low cost per acre, and still produce clean, good quality fruit, both growers and wineries could benefit. Growers would benefit in a number of ways, including the ability to improve the efficiency of their operation (i.e., dollars spent per ton of fruit). Producing more fruit per acre would allow the grower to sell to a winery at a lower price per ton, which could allow a winery to produce a low cost Riesling (<$10/bottle) that could be made in enough quantity to be distributed nationally. This is not to say that growers and wineries should not strive to produce higher priced and higher quality Rieslings as well, as many are doing now. This kind of farming would allow the region’s Riesling market to expand and expose more consumers to wines produced from the Finger Lakes.

So if anybody has a few hundred thousand dollars burning a hole in their pocket, and about 8-10 years to wait for results, give me a call.

Chris Gerling is extension enology associate in the department of food science, based at the NYS Agricultural Experiment Station in Geneva, NY.