Wine Flavor 101C: Bottling Line Readiness Oxygen Management in the Bottle
Annegret Cantu [email protected] Andrew L. Waterhouse
Viticulture and Enology Outline
Oxygen in Wine and Bottling Challenges
. Importance of Oxygen in Wine . Brief Wine Oxidation Chemistry . Physical Chemistry of Oxygen in Wine . Overview Wine Oxygen Measurements . Oxygen Management and Bottling Practices
Viticulture and Enology Importance of Oxygen during Wine Production
Viticulture and Enology Winemaking and Wine Diversity Louis Pasteur (1822-1895):
. Discovered that fermentation is carried out by yeast (1857)
. Recommended sterilizing juice, and using pure yeast culture
. Described wine oxidation
. “C’est l’oxygene qui fait le vin.”
Viticulture and Enology Viticulture and Enology Viticulture and Enology Importance of Oxygen in Wine
QUALITY WINE OXIDIZED WINE Yeast activity Color stability + Astringency reduction
Oxygen Browning Aldehyde production Flavor development Loss of varietal character
Time Adapted from ACS Ferreira 2009 Viticulture and Enology Oxygen Control during Bottling Sensory Effect of Bottling Oxygen
Dissolved Oxygen at Bottling . Low, 1 mg/L . Med, 3 mg/L . High, 5 mg/L
Dimkou et. al, Impact of Dissolved Oxygen at Bottling on Sulfur Dioxide and Sensory Properties of a Riesling Wine, AJEV, 64: 325 (2013) Viticulture and Enology Oxygen Dissolution . Incorporation into juices & wines from atmospheric oxygen (~21 %) by: Diffusion Henry’s Law: The solubility of a gas in a liquid is directly proportional to the partial pressure of
the gas above the liquid; C=kPgas Turbulent mixing (crushing, pressing, racking, etc.)
Increased pressure
More gas molecules Viticulture and Enology Oxygen Saturation . The solution contains a maximum amount of dissolved oxygen at a given temperature and atmospheric pressure • Room temp. 25C
. Saturation with air:
6 mL O2/L (8.4 mg O2/L)
. Saturation with oxygen:
30 mL O2/L (42 mg O2/L)
Viticulture and Enology Oxygen Solubility . Solubility of oxygen with temperature 0°C (32°F) . 0°C = ~15 ppm, 25°C = ~ 8.5 ppm
25°C (77°F)
32°C (90°F)
. Dissolved oxygen decreases http://www.esf.edu/EFB/schulz/Limnology/oxygensolubility.JPG as the temperature goes up
Viticulture and Enology Oxygen Solubility
. Oxygen saturation as a function of ethanol . In wine = ~ 8.5 ppm . 66% v/v = ~15 ppm
60
50
40
30
20 Oxygen (ppm) 10
0 0 1227456680100 Ethanol (%v/v)
. Oxygen solubility as a function of solutes . Decreases with increasing presence of solutes Viticulture and Enology White & Ough, AJEV 1973 Oxygen Depletion . Depletion of oxygen in wine
. Loss due to other gases (e.g. CO2) . Temperature and atmospheric pressure changes
. Oxygen consumption after saturation with air ~ 6 days at 30°C (faster in reds due to polyphenols)
. Total O2 that can be consumed before noticeable oxidation . ~ 85 mg/L for whites . 10 saturations before oxidation noticeable Loss of varietal aroma . ~ 195 mg/L for reds
. 30 saturations before oxidation noticeable10 9 SO2 in model solution . 10 saturation wine would benefit 8 7 6 5 4
Oxygen (mg/L) Oxygen 3 2 White wine Ascorbate in white wine1 0 0 5 10 15 20 Viticulture and Enology Time (Days) Poulton 1970: In Boulton et al., 1996 Oxygen Wine Chemistry
o-diphenol
• Rate of O2 consumption is limited to ferrous iron + phenolic pool
SO2 consumption
• Depleted in the process • F+TSO2 proxy for exposure • Color stabilization • Too much aldehydic aroma
• Browning, whites • Varietal thiols • Tannin softening, reds • Mercaptans
• Methional and phenylacetaldehyde • Honey character /, boiled veggies Viticulture and Enology 101 of Wine Preservation –
O2 and SO2 . SO2 (sulfite) does NOT react directly with oxygen. However, it reacts with oxidation products . Same NET result
. 2 SO2 + O2 → 2 SO3 -2 . (H2SO4, SO4 ) . “Rule of thumb”: 1 mg of oxygen consumes 4 mg of free sulfur dioxide
Viticulture and Enology Oxygen Exposure of Bottled Wine mainly depends on…
(1) the amount of oxygen in the headspace at bottling,
(2) from the closure into the bottle, as a consequence of compression during bottling
(1) 0.1-0.5 mg/L O2 Natural cork
(2) 0.5-1.1 mg/L O2 Synthetic cork (3) Can be similar for screw caps (depending on HS, and inerting of SC)
(3) oxygen ingress into the bottle through the closure,
(4) oxygen ingress into the bottle through the interface closure/ bottle
Viticulture and Enology Oxygen Exposure of Bottled Wine OTR= Oxygen Transmission Rate
The amount of O2 that comes through the closure due to diffusion @ equilibrium.
O2 enters the bottle because of O2 gradient caused by the partial
pressure of O2 inside and outside of the bottle and is dependent on the permeability of the closure.
Permeation depend temperature changes and wine expansion
Silva et al., 2011 Viticulture and Enology Oxygen Exposure of Bottled Wine
Viticulture and Enology Angleosante, 2016 Oxygen Measurements during Bottling For bottles, measure HSO and DO Total Package Oxygen = TPO (mg/L)
http://www.nomacorc.com/analyzers-2/
Viticulture and Enology http://www.oxysense.com Oxygen Measurements Instrument Range, LOD & Calibration PSt3 PSt6 Range 0-22 0-1.8 mg/L mg/L 0-50 % 0-4.2 % Limit of 15 ug/L 1ug/L detection 0.02 h 0.31 hPa (LOD) Pa
http://www.mocon.com/instruments/optech-o2-model-p.html Viticulture and Enology Oxygen Control Before/During Bottling
Where does Oxygen “sneak” in? Measured delta DO 0.180 mg/L @ beginning
Sight glass with O2 sensing dots
Viticulture and Enology Calderon et al., 2014. Cien. Inv. Agr. Oxygen Control Before/During Bottling Where does Oxygen “sneak” in?
Winery Equipment 02 enrichment range (mg/L) Median (mg/L) Average (mg/L) Temperature (°C) Wine style Turbidity Centrifugal pump 0.0029‐0.097 0.049 to 11.6 0.054 whiteracking finished w 11ines Diatomaceous Earth 0.141‐0.177 0.157 to 10.7 0.155 white 200 NTU 10.4 > Tangential flow filter 0.178‐0.229 0.214 to 11.5 0.21 red 11 Centrifuge 0.354‐0.382 0.364 0.367 11.1 to 12.5 red 300 NTU ~ Pad filter (1.0 uM) 0.219‐0.428 0.315 to 11.1 0.331 red 10 n.a. Membrane filter (0.45 uM) 0.125‐0.165 0.147 to 11.5 0.161 red 5 NTU 10 > Rotary vacuum filter 1.992‐2.562 2.296 to 14 2.25 red content high of solids 12 Tartrate stabilization system 2.669‐2.764 2.723 to 2.714(‐5) white (‐4.5) Bulk wine transport oxygen for Red Dissolved Wine 0.201‐0.225 0.201 0.217all wines was below 12 ‐15°C White Wine 0.107‐0.159 0.147 0.1420.180 mg/L 17‐19°C
Viticulture and Enology Calderon et al., 2014 Key Points of Bottling (1) – Study Fresno State
. Different cellar practices have different impacts
. Analysis of O2 uptake during bottling using different closures: 8 natural corks, 5 synthetics, 4 screw cap, 1 agglomerated closure . 17 wineries less than 5,000 gals – 120, 000 gals/ annually . 8 whites and 9 reds
Viticulture and Enology Hend Letaeif, Wines & Vines, 2016 Key Points of Bottling (2) – Study Fresno State
. At each transfer O2 may penetrate and dissolve into the wine . As wine progresses through bottling a so called “U-curve” DO . Start less 1 mg/L DO, maintained below 0.3 mg/L . Reported Data: HS at filling 1.5-2.5 mg/L; DO 2-4 mg/L; closure 0.1-1.1 mg/L ~ 8 mg/L can happen . Oxygen can be closely monitored (TPO @specific points) . Suggested TPO levels below 1.25 mg/L for reds an 0.6 mg/L for whites + rosé . TPO management ultimate goal minimize bottle-to-bottle variation
Viticulture and Enology Hend Letaeif, Wines & Vines, 2016 Key Points of Bottling (3) – Study Fresno State TPO variations were studied on critical cellar operations • Type of wine • Closure + Bottle • Length, hose diameter between equipment • Filling spouts • Bottle volume, line speed • Technology of filling • Priming the circuit • Inert gas usage • Use of vacuum
. TPO variations from 0.6-3.3 mg/L , 2.5 mg/L . Out of 18, 7 failed levels below 1.5 mg/L, bottle-bottle variations, U-curve Viticulture and Enology Hend Letaeif, Wines & Vines, 2016 Key Points of Bottling (4) – Study Fresno State
Speed of bottling run (slow vs. fast) Slower filling and corking or capping, wine stayed longer in
the lines = more O2 pick up Decrease with use of inert gas
Viticulture and Enology Hend Letaeif, Wines & Vines, 2016 Key Points of Bottling (5) – Study Fresno State
Viticulture and Enology Hend Letaeif, Wines & Vines, 2016 Key Points of Bottling (6) – Study Fresno State
Viticulture and Enology Hend Letaeif, Wines & Vines, 2016 Loss of SO2 after Bottling Typical 30 mg/L Free SO2 . Less than 1-2 mg/L TPO, typical for very good bottling for reds
. Consumption of 4-8 mg/L SO2 . 4 mg/L total package oxygen, poor QC on line
. Consumption of 16 mg/L SO2!!!
. Think about SO2 “after bottling”…
Viticulture and Enology Oxygen Control during Bottling -Summary Why do we worry about bottling and post-bottling?
Bottling + closure choice has a significant impact on the contents of DO and HSO in wine
. Too much O2 might cause serious defects - premature aging . “Bottle shock”
. Some O2 might benefit wine in particular red wines
Viticulture and Enology Oxygen Control during Bottling -Summary How to protect the wine from oxygen and pre- mature aging?
Carefully setting up a bottling line . Using inert gases
. Monitoring O2 . Checking equipment (connections, surfaces etc.)
Adding the right amount of SO2
Remember !!! Under const. pressure conditions, the DO conc. exponentially with temperature
Viticulture and Enology Oxygen Control during Bottling -Summary Take Home Message – Setting up a Bottling Line and Sampling Know and monitor your “weak points”
Chose a O2 measuring device that suits your set up best Know the size of your bottling run and chose a
representative sample size
Watch your temperature !!!
Do some pre-testing and validate your own method
Closure’s characteristics - OTR vs wine style Viticulture and Enology Oxygen Wine Chemistry I
O 2 OO + H2O
RC HOH RCHOH Fe+2 Fe+3 + RC=O RCHOH 1 5
O HO O (Hydroperoxyl+ OH (Hydroxyl radical) 2 HO + H2O H+ radical) +3 2 + Fe OH H H 4 OH O OH O O Fe+2 + HOHO (Semiquinone radical) (Hydrogen peroxide) 3
O O
(Quinone) Viticulture and Enology Oxygen Wine Chemistry Wine II
OH OH OH OH Resorcyl
+ OH Polymerization OH H HO
RCHSH Vitisins OH H S Anthocyanins Resorcyl 2 O OH 2 OO RC HOH Fe+2 Fe+3 + RC=O RCHOH RCHOH
HO O (Hydroperoxyl OH O2 + HO (Hydroxyl radical) + H2O OH H+ radical) OH +3 + Fe Ferrous OH OH H H O regeneration OH O +2 O O Fe O by phenolic + HOHO reduction (Semiquinone radical) (Hydrogen peroxide) OH OH OH O OH Resorcyl O RSH OH R HO S (Quinone) Phenolic coupling Sulfide trapping (polymerization) Viticulture and Enology Oxygen Measurement Overview
Spectral methods using a dye (O2 indicator) . Non-destructive . Repeated measures . Model wine only MOCON OxTran (coulometric medthod) . Standard test method for measuring OTR through dry packages
O2 probe on liquid in bottle (electrochemical method) . Orbisphere . Destructive . Reliable Oxygen sensing spots (photochemical method) . Non-destructive and destructive . Repeated measures Viticulture and Enology Oxygen Measurements
Dye O2 Indicator Example . Indigo carmine solution reacts with oxygen . Tristimulus measurement of the consequent color change (yellow; reduced blue, oxidized) . Large sample number possible, Model wine
. O2, light and heat are causes of degradation
Brotto et al., J. Agric.Food Chem., Vol. 58, No.6, 2010
Viticulture and Enology Oxygen Measurements MOCON OxTran (couloumetric detector) Air or Oxygen Atmosphere Steady state ~ 30 days to stabilize
Impermeable glue Metal base plate
GAS IN GAS OUT Nitrogen + oxygen, to oxygen Humidified oxygen-free nitrogen detector
Gibson, ASEV Presentation 2005 Viticulture and Enology Oxygen Measurements MOCON OxTran
Viticulture and Enology Pictures taken at G3 Enterprise 2015 Oxygen Measurements Orbisphere (electrochemical method)
. Electrolysis system: amount of generated current is
proportional to O2 partial pressure
. Destructive method, not as convenient as luminescence method
. Still benchmark; very reliable and established
https://www.etslabs.com/analys Viticulture and Enology s Oxygen Measurements Nomasense (dynamic luminescence) Luminophore Excited with light Decay causes delay in the light signal emitted Decay time in
presence of O2 Correlated to concentration
Viticulture and Enology Rates of Oxidation
Oxidation rates may be defined…
. Loss of O2 once it is induced
. Loss of reduced compounds SO2
. Formation of compounds asscociated with
oxidation, e.g. browning, acetaldehyde Oxygen Control during Bottling Setting up a Bottling Line ‐UC Davis Winery Experience Two Scenarios Scenario 1 • Nomacorc Bottling in 2007 • Mobile Bottling Line • Initial DO 5 mg/L (!! 8.4 mg/L, @ atm. pressure!!) • No-pretrial Response • Bottled by hand with a vacuum driven filler • 6 people doing the job
• Using nitrogen for blowing out O2 in the bottle and later HS
End Result • About 1-2 mg/L TPO Viticulture and Enology Oxygen Control during Bottling
Bottle Preparation
Flushing each bottle
with N2 prior to filling
Nitrogen Drip in-line
Headspace “sparging” before corking
Viticulture and Enology Oxygen Control during Bottling
How did we measure O2 in the bottling line? All equipment Set Up and the Bottle? Luminescent Dots (PST3: range 0-22 mg/L) . non-destructive but dots stay in the bottle Dipping Probe . for tank/barrel measurements
Viticulture and Enology Oxygen Control during Bottling Scenario 2 Bottling Line Set Up at RMI Winery UC Davis 2014
Filler bowl N2 N2 (99.4%) for 30 sec Liquid N2 drip into HS into the empty bottles
. Tank DO 0.35 mg/L,15.4 °C . Filler bowl DO 0.35 mg/L . HS: < 20 hPa . Bottle DO < 0.5 mg/L
. TPO 0.6-1 mg/L, 18.7 °C . Screw cap
Tank under N2 pressure Winemaking and Wine Diversity . Winemaking techniques and wine styles vary widely
Grape juice Wine Water Water Hexoses Ethanol Acids Acids Etc. Etc. O2
Yeast
C6H12O6 2CH3CH2OH + 2CO2 Viticulture and Enology