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w i n e M A K IN G All six compounds showed a much higher rate of extraction for the cross-cut exposed oak compared to parallelexposed oak. The slope results and correlation coefficients are presented in Table I and demonstrate that all compounds are extracted from the cross-cut exposed oak at a faster rate than the same compounds from parallel-exposed oak. Cross-cut exposure of oak likely provides more rapid access of the model wine solution to flavor molecules in the wood through natural pores in the wood. This is demonstrated by the higher rate of extraction for all six molecules measured by HPLC and the higher slope of the absorbance at 465nm. As the samples were controlled for mass, surface area and toast level, the only difference remaining between them was grain exposure. gallic acid had been extracted and additional extraction time would not have resulted in a higher final concentration. The other analytes showed a similar result, reaching a maximum concentration well before the end of the 14-week extraction for both cross-cut and parallelexposed oak samples. The only two molecules that did not have significantly different final concentrations had the smallest molecular weights and the highest water solubilities. These results demonstrate that extrac- tion of larger flavor molecules with lower water solubility can only be maximized by exposure of the cross-cut grain of the oak. In essence, with only parallel grain exposure a larger percentage of the flavor molecules in the oak will not be extracted at any time. This suggests that to maximize flavor from oak and minimize the amount of oak to be used to flavor wine, a crosscut grain orientation must be used in addition to or exclusive of parallel grain exposure. © 2013 StaVin Inc. Final composition (Experiment 2) The final concentration of each analyte is presented in Table II. These numbers are the average of the final concentrations from all three extract solutions for each grain orientation. Figure 6 presents the concentration data for gallic acid in the 14-week period to demonstrate that the concentration of the analytes has reached a static level for both parallel and crosscut-exposed oak solutions. This result was observed for all analytes and the absorbance of the solution. Since replicate extractions were conducted, we were able to perform a statistical comparison of the final concentrations. These results (Table II) show that furfural and 5-methylfurfural concentrations are nearly identical between both types of oak grain exposures. However, the other compounds are at significantly higher concentrations for the cross-cut exposed oak samples. Furfural and 5-methylfurfural have the smallest octanol-water partition coefficients of the compounds in this study (log Kow of 0.41 and 0.67 respectively), though gallic acid has a log Kow of 0.70, close to that of 5-methylfurfural. The fact that the model wine solution has faster access to the oak through the wood pores in a cross-cut grain exposure implies a faster rate of extraction but does not suggest a different final concentration given enough time for extraction. However, in spite of controlling for mass and surface area of the oak we found higher final concentrations of most analytes extracted from the cross-cut exposed oak samples. Figure 6 demonstrates that the parallelexposed oak solution reached a maximum gallic acid concentration at about 10 weeks, indicating that all the available For over twenty years we've searched the world to source the very finest oak known to wine. Our hikes through numerous forests in countries on two continents have yielded findings some winemakers consider treasure. Such travels have shown us the rewards of perseverance, and the importance of variety. Because even the most delicious wines don't always taste the same. ® StaVın Inc, P.O.Box 1693, Sausalito,CA 94966 (415) 331-7849 f (415) 331-0516 stavin.com pr actica l win ery & vin eya r d JANUARY 20 14 25