What Does Oxygen Do to Wine: Aging, Faults, and Storage

What does oxygen do to wine? Its interaction with the bottle is a critical factor in the wine's evolution. That interaction determines whether the wine develops complexity or deteriorates. Controlled, low oxygen ingress is crucial for maturation, allowing complexity and an aromatic bouquet to develop, as J. Robinson notes in "The Oxford Companion to Wine" (2006). This controlled interaction allows a wine to reach its optimal organoleptic characteristics, as Chanut et al. (PNAS Nexus, 2023) explain. Conversely, excessive oxygen exposure can lead to rapid aging, significant deterioration, and the development of "oxidised" or "cooked" characteristics, according to the Australian Wine Research Institute (AWRI). Ough (1986) found that temperatures exceeding 40°C can induce visual and sensory changes in wine in a matter of days. Understanding these mechanisms and managing storage conditions is key to preserving your fine wine collection.

How does oxygen enter a sealed bottle?

Oxygen primarily enters a sealed wine bottle through two main pathways. It comes directly through the cork stopper and, significantly, at the interface between the cork and the glass bottleneck. A study by Chanut et al. (PNAS Nexus, 2023) investigated the oxygen barrier properties of microagglomerated cork-based stoppers over 24 months. They found that the oxygen diffusion coefficient of the cork stopper alone remained unchanged regardless of storage conditions. That held across temperature, storage position, and the presence of model wine.

However, the presence of model wine modified the total oxygen transfer. That total includes both the transfer through the stopper and at the glass-cork interface. Chanut et al. (PNAS Nexus, 2023) observed that in the presence of model wine, the total oxygen diffusion coefficient for the bottleneck-stopper system nearly doubled after three months of storage at 20°C. It rose from 2.3 × 10⁻¹¹ to 4.7 × 10⁻¹¹ m² s⁻¹. This increase was attributed to the presence of model wine favoring oxygen transfer at the glass-cork interface. That interface accounted for nearly 70% of the total oxygen transfer. This phenomenon could be due to the sorption of water and ethanol in the cork. That may favor surface diffusion or modify the cork's mechanical properties. Either change would decrease the force applied by the stopper on the glass surface.

Does bottle orientation affect oxygen ingress?

The impact of bottle orientation on oxygen ingress differs between still and sparkling wines. Research on still wines presents varied findings.

Wine Type	Recommended Orientation	Rationale
Still Wine (cork closure)	Horizontal or slight angle	Keeps cork moist, preventing drying out and potential oxygen ingress. Mas et al. (2002) found that after 24 months, wines stored upright had higher yellow/brown color than those stored horizontally, though differences were not significant; oxidation was higher for upright samples sealed with agglomerated cork stoppers. Skouroumounis et al. (2005) found bottle orientation had little effect on chemical composition and sensory properties of Chardonnay and Riesling wines over 60 months. Chanut et al. (PNAS Nexus, 2023) found no significant influence of storage position (vertical or horizontal) on oxygen transfer through the cork or at the glass-cork interface over 24 months at 20°C.
Champagne / Sparkling Wine	Upright (often recommended) or on its side (Comité Champagne)	Champagne is often recommended to be stored upright because the internal pressure from trapped carbonic gas provides enough humidity and protection from oxygen. Caterer Magazine (2001) reported that a study by the Comité Interprofessionnel du Vin de Champagne (CIVC) found Champagne stored on its side aged more quickly due to oxygen seepage after corks lost elasticity. However, the Comité Champagne (2022) states that Champagne will keep well for several years if stored on its side in a cool, dark, draft-free place.

For still wines, the traditional advice has been to store bottles on their side to keep the cork moist. A dried-out cork could allow oxygen to enter. However, studies like Mas et al. (2002) and Skouroumounis et al. (2005) have shown mixed results regarding the significance of this effect on wine quality. The Chanut et al. (PNAS Nexus, 2023) study focused on microagglomerated corks. It found that the storage position (vertical or horizontal) had no significant influence on oxygen transfer. That held through the cork and at the glass-cork interface over a 24-month period at 20°C.

For Champagne and other sparkling wines that upright storage is often recommended. The internal pressure of the carbonic gas provides sufficient humidity and protection from oxygen. Caterer Magazine (2001) reported a CIVC study on Champagne stored on its side. It aged more quickly because corks lost elasticity, allowing oxygen to seep in. Despite this, the Comité Champagne (2022) itself recommends storing Champagne on its side for several years, provided it is in a cool, dark, draft-free place.

What role does temperature play in oxygen's impact?

Temperature is a critical factor in wine storage. It directly influences the rate of chemical reactions and the integrity of the bottle's closure system. Excessive storage temperatures significantly affect the shelf life of bottled wine. Marais (1986) observed rapid aging and deterioration after 12 months at 30°C. Temperatures above 40°C can induce visual and sensory changes in a wine in just days, according to Ough (1986). In general, any storage place where the temperature exceeds 25°C for long periods and 40°C for short periods can affect wine quality, Ough (1992) states.

The AWRI recommends avoiding thermal cycling, where temperatures vary significantly. That cycling can cause wine leakage and cork movement due to thermal expansion. Such physical damage affects appearance and marketability, even if the wine's quality is not necessarily compromised.

A study by Chanut et al. (PNAS Nexus, 2023) specifically investigated the effect of storage temperature on oxygen transfer through microagglomerated corks in contact with model wine. At 20°C, the total oxygen diffusion coefficient remained unchanged for up to 24 months. However, at 35°C, a temperature easily reached during bottle shipping, a sharp increase in the total oxygen diffusion coefficient was observed after 9 months of storage. At 50°C, this significant increase in oxygen transfer at the glass-cork interface occurred within the first three months of storage. This accelerated transfer at higher temperatures could be attributed to a partial melting of the paraffin and silicone surface treatment on the cork stopper. The other candidate is a modification of the cork's mechanical properties, which would leave a weaker seal.

A wine has a greater potential to develop complexity and a more aromatic bouquet if it ages slowly in a relatively cool environment, as J. Robinson notes in "The Oxford Companion to Wine" (2006). The lower the temperature, the more slowly a wine develops. Most experts, including J. Robinson, recommend constant temperatures between 10 and 15°C (50 and 59°F). Tom Stevenson speculates that 11°C (52°F) may be ideal, while Karen MacNeil recommends around 13°C (55°F) for aging wine. Wine can be stored at temperatures as high as 21°C (69°F) without long-term negative effect. Professor Cornelius Ough of the University of California, Davis, believes wine can withstand temperatures as high as 49°C (120°F) for a few hours without damage. For more on how temperature impacts your collection, explore our guides on how to store wine.

How does humidity influence oxygen transfer?

Humidity plays a role in maintaining the integrity of cork closures. Those closures in turn affect oxygen transfer into the bottle. Cork enclosures need some degree of humidity to avoid drying out. That applies even when bottles lie on their sides, with one side of the cork exposed to air. If a cork dries out, it can allow oxygen to enter the bottle and fill the ullage space. The wine may then spoil or oxidise. You can learn more about how fill levels indicate condition in our guide to wine ullage levels explained.

Excessive humidity, however, can damage wine labels, hindering identification or hurting potential resale value. Jancis Robinson notes that 75% humidity is often cited as ideal. There is little significant research to definitively establish an optimal range. Tom Stevenson recommends against storing wine in a refrigerator. The refrigeration process often includes dehumidifying, which can quickly dry out corks.

Alexis Lichine contends that low humidity can be detrimental to premium wine quality. The risk is the cork drying out. He recommends spreading half an inch of gravel on a wine cellar floor. Periodically sprinkling it with water then maintains optimal humidity. The Comité Champagne (2022) recommends high and constant humidity, between 60% and 80%, for storing Champagne bottles.

Can light exposure affect wine quality?

Yes, exposure to light can significantly affect wine quality, leading to undesirable sensory changes. Light exposure can cause the production of volatile sulfur compounds. The result is what is known as "lightstruck" flavour, according to the AWRI. Maujean and Seguin (1983) demonstrated that this flavour is due to the formation of volatile sulfur compounds. Those are believed to derive from sulfur-containing amino acids. Riboflavin (vitamin B2), present in wine, undergoes photo-activation when exposed to light at wavelengths of 370 nm and 440 nm. That leads to the oxidation of these amino acids and the formation of off-flavours (AWRI Technical Note TN09).

Dozon and Noble (1989) found that still and sparkling white wines in green glass developed a statistically significant lightstruck flavour after 31.1 hours and 18 hours of exposure to fluorescent lamps, respectively. The same wines in clear glass developed this off-flavour much faster, after only 3.3 hours and 3.4 hours. Sensory assessment of affected wines indicated a decrease in "citrus" aromas and an increase in "cooked cabbage," "corn," "wet wool/wet dog," and "soy/marmite" aromas (AWRI Technical Note TN09).

Light-bodied white wines run the greatest risk from light exposure. They often come in tinted bottles for protection. Wines in clear, light green, and blue bottles are most vulnerable. Amber glass is most effective at excluding wavelengths below about 450 nm, according to Rankine (1989) (AWRI Technical Note TN09). Direct sunlight provides significantly more UV-A radiation than fluorescent lamps. Sunlight exposure, such as in retail window displays, is therefore likely more deleterious to wine quality (AWRI Technical Note TN09). In a cellar, wines are often stored in corrugated boxes or wooden crates to protect them from direct light.

What are the ideal storage conditions for long-term aging?

To ensure the longevity and optimal development of your fine wines, consistent and controlled storage conditions are paramount. Amon and Simpson (1986) recommend storing bottled wine with the cork in contact with the wine in a cool (15-20°C), dry location (AWRI). More specifically, most experts, including Jancis Robinson, recommend constant temperatures between 10 and 15°C (50 and 59°F). The Comité Champagne (2022) recommends a constant temperature of between 10 and 15°C for Champagne.

Humidity is also important. The Comité Champagne (2022) advises high and constant humidity, between 60% and 80%, for Champagne. Climate-controlled wine storage holds moderate humidity levels (55%-75%). That range avoids cork shrinkage in dry conditions and mold in overly moist conditions.

Protection from light is crucial. Wines should be stored in a dark environment. Light exposure can lead to "lightstruck" flavour and other quality issues. The Comité Champagne (2022) also emphasizes protecting bottles from light.

Finally, keep vibrations to a minimum. While anecdotal, a study by Chung et al. (2008) found that vibrations could accelerate wine aging, often with negative effects on quality. It concluded that vibrations should be minimized for red wines to limit changes in physicochemical properties. The Comité Champagne (2022) also recommends protecting bottles from vibrations.

For optimal long-term storage, consider a dedicated wine cellar or professional storage facility that can maintain these stable conditions.

To make informed decisions about when your wines are ready to drink or hold, consult our vintage maturity charts. These charts provide insights into the optimal drinking windows for thousands of fine wines. They help you enjoy your collection at its peak.