1. New Ideas for Measuring Oxidation Andrew L. Waterhouse

2. Collaborators Maurizio Ugliano Bruce Currie Stephane Vidal Jean-Baptist Dieval Olav Aagaard Mauri Anderson Alexander Chassy

3. Wine Oxidation Reactions

4. Managing Wine Oxidation Oxygen is consumed Quinone reversal to phenol Limit Fenton oxidation  Quench H 2 O 2  Reactions of Fenton products Color development Measure Oxygen Consumed!

5. Measure Oxygen Consumed in Bottle? Oxygen entering bottle  At bottling  From closure  Oxygen transfer through closure Subtract residual oxygen Balance: consumed oxygen How can we measure oxygen entering bottle

6. Oxygen Measurement in Bottles, etc Device emits blue flashes Dots in container luminesce with red light Rate of decay is related to [O 2 ]

7. Measuring Oxygen Entering Bottle Model Bottle Diéval JB, Packag. Technol. Sci. 2011; 24: 375–385 Provides prediction for the same closures!

8. Oxygen Consumption by Wine Add oxygen entering bottle  Oxygen at bottling  Oxygen from closure transmission (model bottle)  Subtract current O 2 (Nomasense) Difference is Total Consumed Oxygen, TCO Oxygen that has been consumed by wine Apply to an experiment

9. Interaction of Wine Prep, Closures Experiment on Chardonnay Chardonnay Wines  Oak barrel vs SS barrel  Lees aging vs no lees Four Closures  Light  Premium  Premium, 4% O 2  Premium, N 2 Accelerated Aging Experiment  High O 2 at bottling

10. Measurements O 2 by Nomasense Carbonyls by DNPH Phenolics by HPLC SO 2 by Ripper others

11. DO and HSO

12. TCO Data

13. Free SO 2 Data

14. Sulfur Dioxide and Oxygen Theoretical Balanced Reaction  2 SO 2 + O 2 → 2 SO 3 Mass ratio, 4 SO 2 to O 2 So, with 4/1 ratio of consumption  Balanced reaction  Complete protection from oxidation Ratio below 4: oxidation of other components

15. Antioxidant Reactions of SO 2

16. Consumed Free SO 2 /TCO At End of Experiment

17. Different Consumption Ratios Lees aged wine had higher Consumed SO 2 /TCO How can we explain different ratios? Lees aging increases ratio  WM’s report that lees aging is protective  Lees aged wines had less pyruvic acid

18. Relative Reaction Rates of Nucleophiles Nikolantonaki, JAFC, 60: 8484 (2012)

19. Protection of SO 2 SO 2 : Fast rate of reaction with quinones 3-5 mg/L free SO 2 Thiols, 1 ug/L or less  Rate 7x faster than 3MH  Amount >1000x less  Overall SO 2 rate ~ 10,000 times faster Phenolics, 70 mg/L total  Rate 50,000x faster  Overall 5,000 x advantage BUT: free SO 2 is not being depleted as expected

20. Model Quinone SO 2 reaction

21. Effect of Pyruvic Acid Decreases the ability of SO 2 to reduce quinone Compromises the antioxidant effect of SO 2 Need to understand which wine components are affecting these reactions “Weak binders”

22. Measurement of Free SO 2 Titration with I 2 Appearance of excess I 2 after SO 2 depleted

23. Weak SO 2 Binding Agents Pyruvate Alpha-keto glutaric acid Galacturonic Acid Other aldehydes, ketones

24. Barrel Aging on Lees Lower level of pyruvic acid! Yeast lees or bacteria seem to metabolize aldehydes and ketones, reducing them to the alcohol form Thus, the free SO 2 as currently measured, is more available for protective reactions So, during oxidation, the consumed SO 2 /TCO ratio is higher

25. Application of SO 2 /TCO Ratio May be predictive of protection by SO 2 Measurement takes time  At least two time points needed  Need time to consume both oxygen and SO 2 Could a titration of SO 2 versus SO 2 /TCO Ratio show what level of SO 2 could be protective?

26. Improved SO 2 Measurement Predictive of reactive SO 2 Quick measurement Avoids dilution or equilibration effect from titration or other treatment

27. Summary TCO in bottle is a key new measurement  Based on consistent closures Comparison of TCO vs SO 2 consumed appears to be useful  Ratio of 4 indicates no oxidation products  Ratio below 2 leads to significant oxidation  Value below 4 needed for development- phenolics Protection by “free” SO 2 is not linear  Interference by carbonyls? Free SO 2 measures need improvement

28. Major Support Nomacorc American Vineyard Foundation