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64 WINES&VINES December 2015 WINEMAKING PRACTICAL WINERY & VINEYARD percentage) was calculated rela- tive to the oxygen that was sup- plied throughout the year (which is considered to be 100%). On average, the fine-grain American oak barrels supplied wine with 7% of the total yearly oxygen in the first week. After one month, 23% of the total oxygen was supplied. Four months were required to dose the wine with 50% of the total oxygen received in one year. These results suggest that add- ing wine to new barrels before the filling or development of young oaked wine (which corresponds with maintaining these wines in new barrels for two to four months) reduces the potential for barrel oxygenation. For example, if barrels are used for two to four months for one batch of wine and are used for nine months for a second batch of wine, the latter batch would receive only 50% of the potential oxygen that these barrels would provide in one year. We used these results to ex- trapolate the behavior and annual rate calculations for the other eight barrels (four medium-grain American and four fine-grain French oak barrels) between 19 and 24 days during the second phase of the study. After approxi- mately three weeks, the oxygen received by wine in a barrel rep- resents 17% to 20% of the total oxygen that will be received in one year (observed in fine-grain American oak barrels and valid for medium-grain American and French oak barrels). We extracted these and calculated the annual oxygen entry rates for the eight barrels analyzed only during a few weeks instead of one year. Four medium-grain American oak barrels would provide an aver- age of 11.3 mg/L of oxygen per year (B1 = 10.46 mg/L, B2 = 10.64 mg/L, B3 = 11.96 mg/L and B4 = 12.14 mg/L). The annual rate of oxygen supply for four French oak barrels was 8.18 mg/L per year (B9 = 7.93 mg/L, B10 = 8.01 mg/L, B11 = 7.81 mg/L and B12 = 8.97 mg/L per year). For the medium-grain Ameri- can oak barrels, it took 19 days to dose with 17.3% of the total yearly oxygen dose. Therefore, these barrels would provide an average of 11.3 mg/L per year of oxygen to aged wine. Fine-grain French oak barrels were measured after 24 days and provided an average of 1.66 mg/L. Thus, the annual rate of supply for these barrels was 8.18 mg/L per year. Summary We analyzed the kinetics of oak barrel oxygen permeability for one year to establish the kinetics of the annual OTR of a barrel. The results of this study indicated that American oak barrels re- sulted in greater oxygen doses than French oak barrels. In addi- tion, different wood grains (fine and medium) did not signifi- cantly affect the oxygenation rates of the barrels. María del Álamo-Sanza is associated professor in the department of Analytical Chemistry at the University of Valladolid (Spain), where she has been since 2007. She received a Ph.D. in chemistry in 1997 at the University of Valladolid. Her research has always been related to wine chemistry, wine phenolics, oxygen and wine, and the characterization of wine aging in different aging systems and oak woods. Ignacio Nevares Domínguez earned a degree for agricultural engi- neering specialists in agricultural and food industries from the Polytechnic University of Madrid (Spain) in 1991 and a Ph.D. in agricultural engineering from the University of Valladolid in 2003. He is an associated professor at the Depart- ment of Agricultural and Forestry Engi- neering of the Higher Technical College of Agricultural Engineering at the Univer- sity of Valladolid since 2008. For more information, visit oxygenandwine.com. This article was adapted with permission from "Recent Advances in the Evaluation of the Oxygen Transfer Rate in Oak Bar- rels," published Aug. 22, 2014, in the Journal of Agricultural & Food Chemistry. The authors acknowledge the Spanish Ministry of Economy and Competitive- ness (MINECO-FEDER) for financial sup- port (Projects AGL2014-54602-P and AGL2011-26931), and Junta de Castilla y León (Project VA124U14). We acknowl- edge the generous collaboration of Tonel- ería Victoria and Radoux. Your lender of choice for agricultural capital • Agricultural real estate lender for 98 years • Long-term fxed or adjustable rate mortgage fnancing • Real estate secured revolving line of credit • Competitive interest rates • Flexible terms and structuring www.metlife.com/ag Rates are attractive —contact us today. 559.435.0206 Agricultural Investments © 2015 METLIFE, INC. © '15 PNTS The bibliography for this article is available online at winesandvines.com SUBSCRIBE ONLINE & SAVE! winesandvines.com/subscribe Print + Digital Magazine 12 monthly issues a year for $28 winesandvines.com/subscribe