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