Premature oxidation
Encyclopedia
Premature oxidation, is a flaw
that occurs in white wine
s, when the presumably ageworthy
wine is expected to be in good condition yet is found to be oxidised
and often undrinkable. In particular the affliction has received attention in connection to incidents of whites produced in Burgundy
. The afflicted vintage
s are predominantly from the late 1990s, and in particular those of 96, 97 and 98, until 2002. There have also been reports of premature oxidation occurring in wines from Australia
, Alsace
, Germany
, and Bordeaux
.
, MW
has stated that "Poorly-performing corks are the main culprits behind prematurely aged white Burgundy", while Pierre Rovani of The Wine Advocate
has stated the contrary, "corks are not the issue". Allen Meadows
has speculated that "based on what we know today, the most likely source of the problem is cork-related, though it appears this has been exacerbated by generally lower levels of SO2
", while Steve Tanzer believes it to be a combination of several factors that involve corks, global warming
resulting in overripe fruit
, excessive stirring of the lees
, and insufficient use of sulfur dioxide. Roger Boulton, professor of UC Davis, agreed with the probability of multifactorial causality, stating, "there are likely to be both closure issues and wine chemistry
issues, so looking for the [single] answer will be like missing the bus".
The French oenologists
Denis Dubourdieu and Valérie Lavigne-Cruege launched a theory that with the recent trends of abstaining from the use of herbicide
s and letting grass grow freely in the vineyards of Burgundy, the grass competing with vines
for water in conjunction with a warm vintage may cause the vines to endure extreme stress. As a result, grapes grown on highly stressed vines may have insufficient quantities of glutathione
, a compound that functions as an essential antioxidant
during the fermentation
process.
According to Michel Bettane
, Burgundy producers reacted by taking steps to address the possible causes by heightened scrutiny of cork quality, more awareness of possible sulfur dioxide insufficiency, and a decrease of the practice of batonnage, the stirring of the lees that adds richness to the wines but also increases oxygen contact.
In December 2006, Jamie Goode
published an analysis of the problem of premature oxidation in The World of Fine Wine
and explores some possible solutions.
making, in which added sulfite
s are prohibited.
Wine fault
A wine fault or defect is an unpleasant characteristic of a wine often resulting from poor winemaking practices or storage conditions, and leading to wine spoilage. Many of the compounds that cause wine faults are already naturally present in wine but at insufficient concentrations to adversely...
that occurs in white wine
Wine
Wine is an alcoholic beverage, made of fermented fruit juice, usually from grapes. The natural chemical balance of grapes lets them ferment without the addition of sugars, acids, enzymes, or other nutrients. Grape wine is produced by fermenting crushed grapes using various types of yeast. Yeast...
s, when the presumably ageworthy
Aging of wine
The aging of wine, and its ability to potentially improve wine quality, distinguishes wine from most other consumable goods. While wine is perishable and capable of deteriorating, complex chemical reactions involving a wine's sugars, acids and phenolic compounds can alter the aroma, color,...
wine is expected to be in good condition yet is found to be oxidised
Redox
Redox reactions describe all chemical reactions in which atoms have their oxidation state changed....
and often undrinkable. In particular the affliction has received attention in connection to incidents of whites produced in Burgundy
Burgundy wine
Burgundy wine is wine made in the Burgundy region in eastern France, in the valleys and slopes west of the Saône River, a tributary of the Rhône. The most famous wines produced here - those commonly referred to as "Burgundies" - are red wines made from Pinot Noir grapes or white wines made from...
. The afflicted vintage
Vintage
Vintage, in wine-making, is the process of picking grapes and creating the finished product . A vintage wine is one made from grapes that were all, or primarily, grown and harvested in a single specified year. In certain wines, it can denote quality, as in Port wine, where Port houses make and...
s are predominantly from the late 1990s, and in particular those of 96, 97 and 98, until 2002. There have also been reports of premature oxidation occurring in wines from Australia
Australian wine
The Australian Wine Industry is the fourth largest exporter of wine around the world, with 760 million litres a year to a large international export market and contributes $5.5 billion per annum to the nation's economy...
, Alsace
Alsace wine
Alsace wine or Alsatian wine is produced in the Alsace region in France and is primarily white. These wines, which for historical reasons have a strong Germanic influence, are produced under three different Appellations d'Origine Contrôlées : Alsace AOC for white, rosé and red wines, Alsace Grand...
, Germany
German wine
German wine is primarily produced in the west of Germany, along the river Rhine and its tributaries, with the oldest plantations going back to the Roman era. Approximately 60 percent of the German wine production is situated in the federal state of Rhineland-Palatinate, where 6 of the 13 regions ...
, and Bordeaux
Bordeaux wine
A Bordeaux wine is any wine produced in the Bordeaux region of France. Average vintages produce over 700 million bottles of Bordeaux wine, ranging from large quantities of everyday table wine, to some of the most expensive and prestigious wines in the world...
.
Theories
Clive CoatesClive Coates
Clive Coates is a British wine writer and Master of Wine, best known for his books about the wines of Burgundy.-Biography:Born in 1941, Clive Coates worked for The Wine Society in Stevenage in the late 1960s and early 1970s. In 1975 he founded the award-winning magazine The Vine, a monthly fine...
, MW
Master of Wine
Master of Wine is a qualification issued by The Institute of Masters of Wine in the United Kingdom...
has stated that "Poorly-performing corks are the main culprits behind prematurely aged white Burgundy", while Pierre Rovani of The Wine Advocate
The Wine Advocate
The Wine Advocate, informally abbreviated TWA or WA, is a U.S. bimonthly wine publication featuring the consumer advice of wine critic Robert M. Parker, Jr....
has stated the contrary, "corks are not the issue". Allen Meadows
Allen Meadows
Allen Meadows is an American wine critic and publisher of the Burghound.com quarterly newsletter and website. A financial executive and private wine collector until a profile published in Wine Spectator in 1997 led him to decide to follow his passion for wine...
has speculated that "based on what we know today, the most likely source of the problem is cork-related, though it appears this has been exacerbated by generally lower levels of SO2
Sulfur dioxide
Sulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...
", while Steve Tanzer believes it to be a combination of several factors that involve corks, global warming
Global warming
Global warming refers to the rising average temperature of Earth's atmosphere and oceans and its projected continuation. In the last 100 years, Earth's average surface temperature increased by about with about two thirds of the increase occurring over just the last three decades...
resulting in overripe fruit
Ripeness in viticulture
The term ripeness in viticulture can mean different things to different viticulturists and winemakers. At its broadest definition it refers to the completion of the ripening process of wine grapes on the vine which signals the beginning of harvest...
, excessive stirring of the lees
Lees (fermentation)
Lees refers to deposits of dead yeast or residual yeast and other particles that precipitate, or are carried by the action of "fining", to the bottom of a vat of wine after fermentation and ageing. The yeast deposits in beer brewing are known as trub...
, and insufficient use of sulfur dioxide. Roger Boulton, professor of UC Davis, agreed with the probability of multifactorial causality, stating, "there are likely to be both closure issues and wine chemistry
Wine chemistry
Wine is a complex mixture of chemical compounds in a hydro-alcoholic solution with a pH around 3.- Types of natural molecules present in wine :* Acids in wine* Phenolic compounds in wine* Proteins in wine* Sugars in wine* Tryptophol and amino acids derivatives...
issues, so looking for the [single] answer will be like missing the bus".
The French oenologists
Oenology
Oenology,[p] œnology , or enology is the science and study of all aspects of wine and winemaking except vine-growing and grape-harvesting, which is a subfield called viticulture. “Viticulture & oenology” is a common designation for training programmes and research centres that include both the...
Denis Dubourdieu and Valérie Lavigne-Cruege launched a theory that with the recent trends of abstaining from the use of herbicide
Herbicide
Herbicides, also commonly known as weedkillers, are pesticides used to kill unwanted plants. Selective herbicides kill specific targets while leaving the desired crop relatively unharmed. Some of these act by interfering with the growth of the weed and are often synthetic "imitations" of plant...
s and letting grass grow freely in the vineyards of Burgundy, the grass competing with vines
Vitis
Vitis is a genus of about 60 species of vining plants in the flowering plant family Vitaceae. The genus is made up of species predominantly from the Northern hemisphere. It is economically important as the source of grapes, both for direct consumption of the fruit and for fermentation to produce...
for water in conjunction with a warm vintage may cause the vines to endure extreme stress. As a result, grapes grown on highly stressed vines may have insufficient quantities of glutathione
Glutathione
Glutathione is a tripeptide that contains an unusual peptide linkage between the amine group of cysteine and the carboxyl group of the glutamate side-chain...
, a compound that functions as an essential antioxidant
Antioxidant
An antioxidant is a molecule capable of inhibiting the oxidation of other molecules. Oxidation is a chemical reaction that transfers electrons or hydrogen from a substance to an oxidizing agent. Oxidation reactions can produce free radicals. In turn, these radicals can start chain reactions. When...
during the fermentation
Fermentation (wine)
The process of fermentation in wine turns grape juice into an alcoholic beverage. During fermentation, yeast interact with sugars in the juice to create ethanol, commonly known as ethyl alcohol, and carbon dioxide...
process.
According to Michel Bettane
Michel Bettane
Michel Bettane is a leading French wine critic, fortwenty years a writer for the French consumer wine publication La Revue du vin de France until 2004....
, Burgundy producers reacted by taking steps to address the possible causes by heightened scrutiny of cork quality, more awareness of possible sulfur dioxide insufficiency, and a decrease of the practice of batonnage, the stirring of the lees that adds richness to the wines but also increases oxygen contact.
In December 2006, Jamie Goode
Jamie Goode
Jamie Goode is a British author with a PhD in plant biology, and a wine columnist of The Sunday Express. Goode also contributes to wine publications such as Harpers, The World of Fine Wine, Decanter, GrapesTALK and Sommelier Journal....
published an analysis of the problem of premature oxidation in The World of Fine Wine
The World of Fine Wine
The World of Fine Wine, abbreviated WFW, is a British quarterly publication for wine enthusiasts and collectors. Published by Quarto Magazines Ltd, the first issue was released in June 2004. It has been described as "an up-market Decanter, with longer, more in-depth features, more credible tastings...
and explores some possible solutions.
Organic winemaking
Premature oxidation is a risk in organic wineOrganic wine
The most widely accepted definition of Organic wine is wine made from grapes grown in accordance with principles of organic farming, which typically excludes the use of artificial chemical fertilizers, pesticides, fungicides and herbicides....
making, in which added sulfite
Sulfite
Sulfites are compounds that contain the sulfite ion SO. The sulfite ion is the conjugate base of bisulfite. Although the acid itself is elusive, its salts are widely used.-Structure:...
s are prohibited.
External links
- Oxidized Burgundies wiki site internet community project