Oxygen Uptake old problem, new solutions

Transcription

1 Oxygen Uptake old problem, new solutions Carien Coetzee 31 August 2017

2 Percentage Rejections % Faulty cultivar character Microbial decay Insufficient wine and style related character Insufficient colour Mouldy character Thin, watery Sulphur compounds Foreign to wine character Faulty colour Overaged character Volatile character Insufficient cultivar character Turbid, hazy Oxidation

3 Dissolved oxygen (mg/l) Uptake/dissolution Uptake/dissolution vs Consumption 1 0 TIME Not based on real data demonstration purposes only

4 Consumption: Molecules partake in oxidation reactions Development of oxidation colour Loss of pleasant aroma Formation of oxidation aroma Ugliano, 2013

5 Main factors contributing to oxygen dissolution and consumption rate Exposure/Turbulance Temperature The oxygen uptake on an undisturbed surface can be significant! surface area

6 DISSOLVED OXYGEN CONCENTRATION Effect of temperature on oxygen dissolution and consumtion A drop of 5 C solubility increases with 10% Reaction rate is also slower at lower temperatures TIME lower temperature higher temperature Not based on real data demonstration purposes only

7 Main factors contributing to oxygen dissolution and consumption rate Exposure/Turbulance Temperature Catalysts Enzymes Metals

8 Effect of enzyme presence on oxygen dissolution and consumption Fast consumption of oxygen by enzymes 0.5 mg/l/min With enzymes Without enzymes Not based on real data demonstration purposes only

9 Main factors contributing to oxygen dissolution and consumption rate Exposure/Turbulance Temperature Catalysts Enzymes Metals Presence of antioxidants SO 2 :O 2 loss 4:1 (variable) If this ratio is lower it could be problematic: O 2 is oxidizing other compounds

10 Harvest Destemming Crushing Red wine White wine Maceration Cold Soak Maceration / Pumpover Completion of fermentation Malolactic fermentation More intentional oxygenation takes place Stabilization / Clarification Filtration Bottling Aging

11 Harvest Destemming Crushing Red wine OXIDATION ENZYMES White wine Maceration Cold Soak Maceration / Pumpover Completion of fermentation Malolactic fermentation The amount of oxygen uptake between the harvest and the arrival in the tank is variable Stabilization / Clarification Filtration Bottling Aging

12 Harvest Destemming OXIDATION ENZYMES White wine Crushing Red wine Cold Soak Crusher size and design do appear to influence the amount of oxygen that can be taken up by the must Maceration Maceration / Pumpover Completion of fermentation Malolactic fermentation Stabilization / Clarification Filtration Bottling Aging AWRI 2010, Technical Review No. 189 Day, 2012 AWRI

13 Harvest Destemming Crushing Red wine OXIDATION ENZYMES White wine Maceration Cold Soak Maceration / Pumpover Completion of fermentation Malolactic fermentation Stabilization / Clarification Filtration Bottling Aging

14 Harvest OXIDATION ENZYMES White wine Maceration Destemming Crushing Red wine Cold Soak Maceration / Pumpover Completion of fermentation Malolactic fermentation Stabilization / Clarification Filtration Bottling Aging AWRI 2010, Technical Review No. 189 Day, 2012 AWRI

15 Harvest Destemming Crushing Free run splashing in tank Deflation and crumble Red wine Splashing in tank White wine Maceration Cold Soak Pump Maceration / Pumpover Completion of fermentation Malolactic fermentation Stabilization / Clarification Filtration Bottling Aging

16 Harvest Destemming Crushing Red wine Inert press Never reached more than 0.18 mg/l White wine Maceration Cold Soak Maceration / Pumpover Completion of fermentation Malolactic fermentation Stabilization / Clarification Filtration Bottling Aging

17 Harvest Destemming White wine Maceration Crushing Red wine Cold Soak Maceration / Pumpover Yeast use oxygen to synthesize fatty acids and sterols need it early on in fermentation At the beggining of fermentation sufficient oxygen is present quickly consumed and CO 2 formation Yeast needs about 10 mg/l O 2 Completion of fermentation Malolactic fermentation Adding controlled amounts of oxygen at this stage should not cause oxidation No later than 10% v/v alcohol Stabilization / Clarification Filtration Bottling Aging

18 Harvest Destemming Crushing Red wine White wine Maceration Cold Soak Maceration / Pumpover Completion of fermentation Malolactic fermentation Pump over with aeration / venturi 2.5 mg/l Pumping the must so that it first falls into an open tray or bin, and then goes back into the fermenter (usually inundating the cap) 1.5 mg/l oxygen. Stabilization / Clarification Filtration Bottling Include a fan to constantly replace the gas with fresh air 4 mg/l Using a stainless diffusion stone with air 4 mg/l Aging

19 Harvest Destemming Malolactic fermentation Reductive atmosphere Slow release of CO 2 White wine Maceration Crushing Red wine Cold Soak Maceration / Pumpover Completion of fermentation Aging on yeast lees Yeast cells absorb dissolved oxygen mg/(l.h) per 10 9 of yeast cells from 2 nd to 6 th month of aging at 14 C If lees left too long and compacted produce volatile S compounds Bâtonnage is not inherently oxidative since oxidation is buffered by the absorption of oxygen by the yeast Malolactic fermentation Stabilization / Clarification Filtration Bottling Aging Fornairon-Bonnefond et al., 1999

20 Harvest Destemming Crushing Red wine Pumping and racking White wine Maceration Cold Soak Maceration / Pumpover Completion of fermentation Malolactic fermentation Potential to saturate Air leaks in the pump Air leaks in the suction line Stabilization / Clarification Filtration Bottling Aging

21 Harvest Destemming Crushing Red wine White wine Maceration Cold Soak Maceration / Pumpover Completion of fermentation Malolactic fermentation Stabilization / Clarification Filtration Bottling Aging Catarino et al., 2014

22 Harvest Destemming Crushing Red wine White wine Maceration Cold Soak Maceration / Pumpover Completion of fermentation Malolactic fermentation Operate the filtration unit according to the manufacturer s directions make sure all connections and pads are tight Stabilization / Clarification Purge air from the filter pads and transfer lines Filtration Bottling Aging Ben Aziz et al., 2016

23 Harvest 4-5 mg/l O 2 White wine Destemming Crushing Red wine Cold Soak Major sources of oxygen diffusion wine transfer filling/filler headspace levels of the bottling tank headspace in bottle Maceration Maceration / Pumpover Completion of fermentation Malolactic fermentation Bottling vacuum and flushing of bottles before filling filler bowl should be covered length of fill spouts type and force of the jet flush headspace Stabilization / Clarification Filtration Bottling Aging

24 Headspace variability often the cause of bottle differences Use inert gas to flush the headspace Liquid N 2 dosage before closing Vacuum filler Time lapse from filling to closing should be as short as possible

25 DO declined fairly slowly, taking up to 200 days to drop below 0.5 mg/l Most of the initial HS oxygen was consumed within the first days Waterhouse et al., 2016

26 Harvest Destemming White wine Maceration Crushing Stabilization / Clarification Filtration Red wine Barrel: mg/l/year barrel Bottles: Closure type and permeability Cold Soak Maceration / Pumpover Completion of fermentation Malolactic fermentation Bottling Aging Keller, Vinperfect

27 Lopes, 2007

28 White wine Maceration Harvest Destemming Crushing Red wine Cold Soak Maceration / Pumpover Completion of fermentation When to measure oxygen There are several stages where it is important to measure dissolved oxygen BEFORE/AFTER Malolactic fermentation ensures equipment efficiency throughout the production process Stabilization / Clarification Filtration Cannot measure O 2 use SO 2 as a guideline Careful! Bottling Aging

29 Dissolved Oxygen (DO) and Total Package Oxygen (TPO)

30 screwcap screwcap screwcap screwcap cork cork cork cork screwcap

31 DO and TPO When to measure what?

32 How to sample Bottom/top of the tank Temperature Flush sampling bottle with inert gas Fill bottle slowly Leave as little as possible HS Ensure tight closure Measuer oxygen ASAP Du Toit, 2005

33 DISSOLVED OXYGEN MG/L Not based on real data demonstration purposes only Bottling DAYS

34 DISSOLVED OXYGEN (MG/L) white wine can consume 10 air saturations (about 65 mg/l) Red wine can consume 30 air saturations (about 195 mg/l) Before the wine takes on an oxidised character DAYS Not based on real data demonstration purposes only Singleton 1987

35 Purge lines/tanks before filling Fill tanks from the bottom Blanket wines with inert gas Keep tanks full Regularly inspect equipment (pump seals etc) Sparge wine Temperature Reduce turbulance when wine is cold Consider treatments other than cold stabilization Remove metals Prevent enzymatic oxidation Be smart Be informed Be prepared Measure DO and TPO at stragetic points Sample correctly

36 Oxygen Uptake old problem, new solutions Acknowledgements SAWIS, Werner Victor, Marisa Nel References