Addition Rate of Exogenous Tannin for Optimal
Retention in Hybrid Red Wines
Alex J. Fredrickson, Masters Candidate; David C. Manns, Sr. Research Associate;
Anna Katharine Mansfield, Assistant professor, Cornell Enology Extension Laboratory,
Cornell University
ABSTRACT
Winemakers often add exogenous products to increase tannin content in red hybrid
wines, but the recommend dosage of 50-400 mg/L may not effectively increase
condensed tannins. In 2013, wines were made from Marèchal Foch, Corot noir, and
Cabernet Franc to compare the retention of exogenous tannins in interspecific hybrids
and V. vinifera. For each cultivar a commercial exogenous tannin product (tannin 1),with
a condensed tannin concentration of 38%, was added at a rate of 400, 800, and 1200
mg/L after crush and before yeast inoculation. Additions of 800 and 1200 mg/L resulted
in lower final tannin concentrations in Maréchal Foch than in Corot noir and Cabernet
Franc (72.2, 123.8, and 120.4 mg/L at 800 mg/L additions, and 129.8, 219.3, and 244
mg/L at 1200 mg/L, respectively). Though concentrations of condensed tannins were
higher in all wines, none were as high as expected, given the measured concentration
in tannin 1 additions. This study suggests that high concentration additions of
exogenous tannin increase the condensed tannins in hybrid red wines, but not to the
same extent as equivalent additions in wines produced from red V. vinfera cultivars.
BIOGRAPHY
Alex Fredrickson is a M.S. Candidate in Enology at Cornell University, with research
focusing on the addition and retention of tannins in hybrid red wines. Alex received his
B.S. in Food Science from the University of Idaho in 2012, where his studies focused on
food microbiology. Upon graduation, he worked as a winemaking intern at E&J Gallo’s
Sonoma facility in Healdsburg, CA, and as a harvest cellar intern at Church Road
Winery in Hawke’s Bay, New Zealand. In 2014, Alex received the Best Enology Paper
award from the American Society of Enology and Viticulture – Eastern Section for his
work on exogenous tannin additions during red hybrid winemaking.
2015 New York State Biotechnology Symposium • May 12 & 13, 2015
At Brookhaven National Laboratory, Upton, NY