Christian ButzkeEnology Professor
[email protected] www.indyinternational.org www.indianaquality.org
SO2 & Sorbate Management
Oxygen Management
Skin Contact Time
Residual Nutrients
Temperature, pH & Browning
Bulk & Bottle Storage
SO2 & Sorbate Management
Oxygen Management
Skin Contact Time
Residual Nutrients
Temperature, pH & Browning
Bulk & Bottle Storage
SO2 DeficienciesExample: 26 Traminettes
Deficient!
Fine!
Free SO
2.9 3.2 3.5 3.8 4.12.9 3.2 3.5 3.8 4.1
- 150- 150
SO 2molecular
pHpH
Free SO2required
- 75- 75
- 0- 0
(mg/L)
SO2 Management
pH and Required SO2
Free SO2 = 0.85 • (1 + 10pH - 1.83)required
Or see chart @www.indianaquality.org/FreeSO2(pH)Pro.pdf
Free SO2 Decline
Percentage of decline in SO2 for 3 different temperatures
Sorbic Acid
Yeast growth inhibitor: 200 mg/L
Legal limit: 300 mg/L
Sensory threshold: 135 mg/L
Some yeasts are resistant!
NO effect against bacteria
Likely effective against Brett
Added as potassium salt (Sorbate @ 268 mg/L)) => Watch cold stability!
Basics
Sorbic acid + Malolactic bacteria
Cause
PreventionAvoid sorbate as preservativeUse sorbate only with proper SO2
Add no earlier than day before bottlingAlways bubble test/sterile filterNO removal option from wine
Geranium Off-Odor
Sorbate sensitivity:
Malolactic bacteria? NO!
Saccharomyces? YES!
Brettanomyces? MAYBE?
Sorbate Management
Sorbate
I mixed up potassium sorbate and citric acid together to make a sorbate addition and an acid adjustment prior to bottling.
An amorphous white precipitate has formed and is floating on top of the mixture.
What is it and what should I do about it?
© Winemaking Problems Solved
Mixing
Sorbate Mixing
SO2 & Sorbate Management
Oxygen Management
Skin Contact Time
Residual Nutrients
Temperature, pH & Browning
Bulk & Bottle Storage
Presumed White Wine Aging
© Joanna Simon: Discovering Wine
Average white wine
© Vernon L. Singleton: Principles and Practices of Winemaking
Oxygen Management
Oxygen Pickup at Bottling
Oxygen Basics Air-O2 solubility (68˚F): 8 mg/L
Air-O2 uptake at bottling 0.17 - 8 mg/L Uptake per topping: 5 mg/L Uptake per racking: 20 mg/L Uptake via cork: 0.1 - 100 mg/L
Young white wine:• Total O2 uptake capacity: <100 mg/L• Optimum O2 uptake: 0 mg/L
Young red wine: Total O2 uptake capacity: 4,000+ mg/L Optimum O2 uptake: 60 - 130 mg/L
Added Added Addedat the filler via headspace Total O2
Gravity flow filler only 6.60 1.40 8.00
Removed Removed Removedat the filler from headspace Total O2
1. Vacuum pulled at filler 6.00 - 6.00
2. Bottle sparged with N2 0.51 0.02 0.53
3. Vacuum pulled at corker - 0.15 0.15
4. Headspace sparged with N2 - 1.15 1.15
#1- #4 implemented 6.51 1.32 7.83
[mg O2/L]
= 98%
Oxygen Pickup at Bottling
Uptake via cork: 0.1 - 100 mg/L
Oxygen Pickup after Bottling
Oxygen Pickup after Bottling
O2 uptake at bottling: 0.17 - 8 mg/L
SO2 Loss at/after Bottling
⇒ 8 mg O2 + 32 mg SO2 => Sulfate
= Free SO2 Loss
+ additional losses during filtration etc
⇒ Add 10 – 40 mg/L EXTRA SO2before bottling
pH and Required SO2
Free SO2 = 0.85 • (1 + 10pH - 1.83)required
Or see chart @www.indianaquality.org/FreeSO2(pH)Pro.pdf
SO2 & Sorbate Management
Oxygen Management
Skin Contact Time
Residual Nutrients
Temperature, pH & Browning
Bulk & Bottle Storage
Skin Contact Time
Terpene Degradation
... our Traminette had skin contact for 24 hours ...
When considering skin extraction, the contact time is as important as the temperature of the incoming fruit.
Contact time for t1 = 24 hours at 39°Fis roughly equivalent to t2 = 7 hours at T = 59°F
Assumed terpene/tannin extraction kinetics:t2 = t1*1/(3(T-39)*0.056)
SO2 Inhibition of Browning Enzymes
Polyphenol oxidases
• Tyrosinase (from grape) ? YES!
• Laccase (from Botrytis) ? NO!
Option: HTST juice pasteurization
• Esters– Caprate C10– Laurate C12– Pelargonate C9– Caprylate C8– Myristate C14
Fermentation “Aroma”
Expect hydrolysis in 6 weeks to 6 months!
ISSUES
Pre-mature aging?=> No aging potential
Enzyme vs. natural acid hydrolysis?=> Release of non-varietal aromas
Removal of stable anthocyanin-glucoside?
Additional bentonite fining needed!
Treatment
EVC
EVC
EVC
EVC
EVC
EVC
EVC
EVC
EVC
EVC
EVC
EVC
EVC
EVC
EVC
EVC
EVC
EVC
EVC
EVC
SO2 & Sorbate Management
Oxygen Management
Skin Contact Time
Residual Nutrients
Temperature, pH & Browning
Bulk & Bottle Storage
Wine Nutrient Status
Do you know how much you’ve got?
• Residual sugars• Nitrogen• Phosphate• Potassium• Vitamins • Sterols• Other growth factors
Hybrid Nutrient Status By Grape Varietal
(Primary Amino Nitrogen by NOPA)
250 mgYAN/L
250 mgYAN/L
Re-fermentation RulesResidual Sugar• Recognition threshold for sweetness is about 5 g/L (0.5%)• 1 to 4 g/L can smoothen a wine without making it taste off-dry.
Microbial Stability • Sensory perception of dryness is different from microbial stability • Wine is dry when its combined fermentable sugars are below 1 g/L (0.1%).• Considering all reducing sugars, incl.pentoses, 2 g/L (0.2%) is dry. • Even below 2 g/L, R.S. can serve as a substrate for our spoilage microbes.
Gas Production• 1,000 mg/L R.S. can produce almost 500 mg/L CO2 gas. • To push corks about 1,400 mg/L at room/bottling temperature are required.• Strongly influenced by headspace volume and closure type. • A perceivable spritz may be tasted at 800 mg/L CO2 (from 1.6 g/L R.S.).
Haze Formation• S.c. may grow if the recommended doses of sorbate and SO2 are not met.• Or if sterile filtration prior to bottling was compromised (use bubble test!). • Even 100 mg/L residual pentoses can lead to a visible Brett haze. • Visible haze due to S.c. must be expected above 1,000 mg/L R.S.
Yeast
Malic Acid • Grapes at harvest contain between 0.6 and 6 g/L of malic acid• Malolactic bacteria turn malic acid into lactic acid and carbonic acid (CO2) • Tartaric acid cannot be metabolized by wine bacteria. • Absence of a malic acid spot on a paper chromatogram indicates > 30 mg/L.• A barely visible spot about 200 mg/L. • In wine which completed MLF, residual malic acid is less than 300 mg/L (0.3 g/L).
Gas Production• Malic acid is converted into two thirds lactic acid and one third CO2
• 300 mg/L residual acid could produce 100 mg/L gas. • A perceivable spritz may be tasted at 800 mg/L CO2 (from 2.4 g/L malic).
Haze Formation• Visible haze in a white wine due to the growth of Oe. oeni above 300 mg/L.
Re-fermentation RulesBacteria
SO2, Alcohol & MLF
Oenococcus oeni suppression:
• free SO2 to 0.85 molecular at 12% EtOH
• free SO2 to 0.6molecular at 14% EtOH
SO2 & Sorbate Management
Oxygen Management
Skin Contact Time
Residual Nutrients
Temperature, pH & Browning
Bulk & Bottle Storage
Browning & Temperature
% of 50°F Cellar Life
Browning & pH
Dr. Vern SingletonProfessor of Enology EmeritusUC Davis
SO2 & Sorbate Management
Oxygen Management
Skin Contact Time
Residual Nutrients
Temperature, pH & Browning
Bulk & Bottle Storage
www.indianaquality.org
Bottle Storage and Aging
Whites better off at 32 to 40°F?
Wine Shipments
Temperature-controlled trucks that maintain a steady55 degrees will be used to ship to FedEx hubs.
Further Reading
Executive Summary
SO2
O2
°F