ASEV Announces 2026 Best Paper Awards: New Research Challenges Pinot noir Yield Assumptions, Reveals Effect of Berry Size on Zinfandel Wine Style

DAVIS, Calif., April 13, 2026 — The American Society for Enology and Viticulture (ASEV) has announced the recipients of its 2026 Best Paper Awards, recognizing two studies that offer practical insights for vineyard management and winemaking decisions.

Published in the American Journal of Enology and Viticulture (AJEV), this year’s selected papers examine long-standing assumptions about yield management in Pinot noir and the role of berry size in shaping Zinfandel wine composition and sensory profile.

“These papers stand out for their ability to test widely held assumptions and provide clear, data-driven guidance for the industry,” said ASEV Board President James Osborne. “Both studies translate complex research into practical insights that growers and winemakers can apply directly in their operations.”

Best Viticulture Paper

Long-term Citizen Science Project Led to Pinot noir Yield Management Changes by Kiley M. Osterman, former graduate student at Oregon State University and currently with Vina Quest, Paso Robles, California and Patricia A. Skinkis of Oregon State University, Corvallis.

A decade-long study in Oregon’s Willamette Valley found that reducing yields through cluster thinning did not consistently improve fruit or wine quality in Pinot noir. The research, conducted in collaboration with growers across multiple vineyard sites, showed that seasonal conditions had a greater influence on outcomes than yield level.

As a result, participating growers increased yield targets over time without compromising quality, while also reducing labor costs associated with thinning. The findings challenge a widely held assumption in premium grapegrowing and suggest a shift toward site-specific yield management based on vineyard conditions rather than fixed targets. Read the study here

Best Enology Paper

Influence of Berry Size on California-Grown Zinfandel Grapes and Wines by L. Federico Casassa, Nathaniel R. Palmer, Allison V. Donegan, Shea K. Forrey, and Daniel A. Postiglione of California Polytechnic State University, San Luis Obispo; Anibal A. Catania of Instituto Nacional de Tecnología Agropecuaria in Mendoza, Argentina; and Jean C. Dodson Peterson of Washington State University, Tri-Cities.

A multiyear study in Paso Robles found that smaller berries within Zinfandel clusters — particularly raisins — have a disproportionate effect on wine composition and style. Wines produced from smaller berries showed higher alcohol, deeper color, and greater tannin concentration, with more intense spicy and dried-fruit characteristics.

In contrast, wines made from larger berries were lower in alcohol and phenolics, with brighter red fruit character and higher perceived acidity. The study demonstrates that berry size influences wine style through differences in skin-derived compounds, providing winemakers with a clearer understanding of how berry composition can be managed to influence alcohol, structure, and flavor profile. Read the full paper here.

Each year, ASEV’s Best Paper Awards Committee reviews all research published in AJEV and selects one paper in viticulture and one in enology based on scientific merit and relevance to the industry. For more information about the Best Papers Award, click on this page.

Both papers are available to read free of charge on the AJEV website and will be recognized at the Joint 77^th ASEV National Conference and 50^th ASEV Eastern Section Annual Conference in Boise, Idaho.

About ASEV
The American Society for Enology and Viticulture is an international community of wine and grape professionals that promotes industry vitality through the exchange of information and support of research and education. ASEV hosts the National Conference in June and co-hosts the Unified Wine & Grape Symposium in January. ASEV publishes the online American Journal of Enology and Viticulture (AJEV) and awards scholarships to students pursuing a degree in enology, viticulture, or in a curriculum emphasizing a science basic to the wine and grape industry.