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Jonathan R. Cave, Andrew Waterhouse, Nick Gislason
University of California, Davis
Viticulture and Enology
GoalComprehensive model of oxygen availability, necessity, benefit, and detriment from vine to glass
Winery Operations
Cap Manipulation
Racking
Crush
Pressing
Barreling Down
Bottling
Aerative PumpoversSplash Racking, Rack and Return,
Delestage-ish
High Anticipated Oxygen Solvation
Desired Oxygen Uptake
Early in Fermentation - Low EtOH/High Sugar
SO2 - Oxygen scavenger and Interaction Inhibitor?
Winery Operations
Cap Manipulation
Racking
Crush
Pressing
Barreling Down
Bottling
Oxygen’s Role in Fermentation
Measurement PreSens Oxygen Sensor Spots 4
0.5cm, Physically Divided (Sight Glass)
Flow Rate Independent
Fiber Optic - Fluorescence Quenching
[O2] = f(Luminescence Decay)
pH, CO2, H2S, SO2, Ionic Species
Chemical Tolerance – NaOH, H2O2, HCl
CIP - autoclave, steam
Linear Range 0-1800 ppb Accuracy ± 1 ppb LOD: 1 ppb
Non-Invasive
Real-time
Non-Destructive Does not consume
oxygen
No Interference/Cross-Sensitivity
Cleanable/Sanitizable
Dissolved Oxygen Range
Experimental Requirements
Observed 29 Pumpovers 23 Aerative 6 Closed Controls
Within first 3 days of fermentation
Pumpovers by experienced cellar staff Well practiced technique Not harvest interns
No alteration by experimenters
No interference in the production process
Required Observational Treatments
Experimental Design
Oxygen Sensor Spots– Paired Values
Drop – Distance from Screen to Wine
Splash – Radius and WallsFlow Rate – From Racking ArmFlow Type – Screen interaction
Parameters
Two ConditionsDrop – Large/Small
10” vs. 4”Splash – Intense/Mild
Spread and ArcingFlow Rate – Fast/SlowFlow Type – Turbulent/Laminar
Range: 70 - 2300 ppb
Closed PO Control – 0 ppb
Drop – Most Relevant STEV of lower [O2] too high
CV > 75%
Oxygen Solvation/Assimilation Data
Oxygen Assimilation for main observable Treatments
Splash Flow Rate Flow Type Drop
Intense Mild Fast SlowTurbule
ntLamina
r Large Small
Average (ppb)
1563 573 1102 518 1473 947 1282 205
STDEV 553 500 874 564 536 717 643 183
t-Test: Two-Sample Unequal VariancesLarge Small
Mean 1282 205Variance 412948 33518Observations 93 28df 119t Stat 14.3P(T<=t) one-tail 5.4x10-28
t Critical one-tail 1.66P(T<=t) two-tail 1.1x10-27
t Critical two-tail 1.98
Non-Separable TreatmentsCoincident Treatments
Interdependence of Rate, Type and Splash
Cannot discern combination of effects or sole influence
Drop is the only separable Parameter
This is not to say they are irrelevant – need more data
Data Analysis
Treatment OccurrenceTurbulent with Large Drop
95%
Turbulent with Small Drop
5%
Laminar with Large Drop
77%
Laminar with Small Drop
23%
Total Turbulent 27%Total Laminar 73%
Experimental Variation of Large DropWe should expect no significant difference
Enough variability that operations are unpredictable
Distinct groups within the single treatment
Combination of effects may attribute to variation
Refinement of current technique is necessary
Variability
Large Drop Treatment ANOVA
Df Sum Sq Mean Sq F value Pr(>F)
Experiment
14 29417359 2101240 23.015 < 2.2e-16 ***
Residuals 76 6938609 91297
Experiment
Average (ppb)
Statistical Group
27 343 a16 416 a24 700 ab13 878 ab22 945 ab11 966 ab25 1231 bc8 1248 bc7 1277 bc5 1330 bc
17 1623 cd15 1681 cd6 1826 cde9 2197 de
23 2286 e
Conclusions and Future Work
1.) Andreasen, A. A., & Stier, T. J. B. 1953. Anaerobic nutrition of Saccharomyces cerevisiae. I. Ergosterol requirement for growth in a defined medium. Journal of Cellular and Comparative Physiology, 41, 23–36
2.) Andreasen, A. A., & Stier, T. J. B. 1954. Anaerobic nutrition of Saccharomyces cerevisiae. II. Unsaturated fatty acid requirement for growth in a defined medium. Journal of Cellular and Comparative Physiology, 43, 71–281
3.) Ough, C.S. and M.A. Amerine. 1988. Methods for analysis of musts and wines, 2nd, Wiley, New York.
4.) Huber, C., T.-A. Nguyen, C. Krause, H. Humele and A. Stangelmayer. 2006. Oxygen ingress measurement into pet bottles using optical-chemical sensor technology. BrewingScience 5-15.
References