How to Tell If Wine Has Gone Bad: Signs of Spoilage

Knowing how to tell if wine has gone bad comes down to two checks: physical signs of damage, and sensory changes that indicate spoilage. Visual assessments cover leakage and closure damage, as noted by the Australian Wine Research Institute (AWRI). They also cover wine travel or seepage on corks, increased ullage, and label damage. For white wines, chemical analysis includes colour development, specifically yellow or brown colour measured by OD420, according to the AWRI. For red wines, chemical analysis includes spectral measurements for colour and phenolics. Wines exposed to extreme temperatures tend to lose their fresh fruity characters and show more developed fruit characters. At extreme levels of temperature exposure, oxidised and cooked characteristics appear, as the AWRI reports. Robert Parker (2008) suggests that between 10 and 25% of wines sold in the USA have been damaged due to exposure to extreme heat.

What are the signs that wine has gone bad?

Wine quality can deteriorate for several reasons. Visual and sensory changes are the key indicators. The AWRI states that temperatures in excess of 40°C will change a wine. Visual and sensory changes appear in only a matter of days (Ough 1986). Excessive storage temperatures can lead to rapid ageing and significant deterioration. Marais (1986) observed faulty flavours and decreasing overall quality after 12 months’ storage at 30°C.

Physical signs of spoilage include:

• Leakage and Closure Damage: Wine leakage or movement of cork stoppers can occur due to thermal expansion. It follows exposure to temperatures significantly greater than ambient, as reported by the AWRI.
• Increased Ullage: Visual assessments for heat damage include increased ullage, according to the AWRI. Our guide to wine ullage levels explained helps you spot significant changes.
• Label Damage: The AWRI also notes that label damage can be a sign of heat exposure. Such physical damage affects the appearance and marketability of the wine. The quality is not necessarily affected, the AWRI states.
• Cork Pushed Out: Wine exposed to temperatures that are too cold can freeze and expand. That expansion can push the cork out or crack the bottle, which allows more oxygen exposure.

Sensory signs of spoilage include:

• Colour Changes: For white wines, colour development can indicate heat damage, according to the AWRI. Yellow or brown colour is the signal. Light-bodied white wines run the greatest risk from light exposure. For that reason, tinted wine bottles that offer some protection from light are common.
• Developed Fruit Characters: Wines exposed to extreme temperatures tend to lose their fresh fruity characters. They show more developed fruit characters instead, the AWRI reports.
• Oxidised and Cooked Characteristics: At extreme levels of temperature exposure, the AWRI observes oxidised and cooked characteristics. A note on long periods above 77 °F (25 °C). The wine may develop off-flavors that taste raisiny or stewed.
• Lightstruck Flavour: Light exposure can affect the taste of a wine through the production of volatile sulfur compounds. AWRI Technical Note TN09 calls the result ‘lightstruck’ flavour. Dozon and Noble (1989) exposed still and sparkling white wines in green glass to fluorescent lamps. Lightstruck flavour appeared after 31.1 hours and 18 hours respectively. Wines in clear glass developed it after only 3.3 hours and 3.4 hours respectively.

How does temperature affect wine quality?

Temperature control is an important consideration in wine storage. Wine is very susceptible to changes in temperature. Excessive storage temperatures have a marked effect on the shelf life of bottled wine. The result is rapid ageing and significant deterioration, according to the AWRI. Marais (1986) observed faulty flavours and decreasing overall quality after 12 months’ storage of wine at 30°C. Temperatures in excess of 40°C will induce visual and sensory changes to a wine in only a matter of days (Ough 1986). In general, any storage place above 25°C for long periods can affect wine quality. The same goes for 40°C over short periods (Ough 1992), as the AWRI reports.

Most experts, such as Jancis Robinson, recommend a constant temperature between 50 and 59 °F (10 and 15 °C). Tom Stevenson speculates that 52 °F (11 °C) may be the most ideal temperature for storage and aging. Karen MacNeil recommends a cool area for wine intended for ageing. She puts the constant temperature at around 55 °F (13 °C). Wine keeps at temperatures as high as 69 °F (21 °C) without long-term negative effect. Professor Cornelius Ough of the University of California, Davis, believes that wine can be exposed to temperatures as high as 120 °F (49 °C) for a few hours and not be damaged.

However, temperature swings can cause adverse chemical reactions in the wine. Repeated transfers from a warm room to a cool refrigerator are the classic case. Those reactions may lead to a variety of wine faults. The lower the temperature, the more slowly a wine develops. On average, the rate of chemical reactions in wine doubles with each 18 °F (10 °C) increase in temperature.

A study by Chanut et al. (2023) on microagglomerated cork stoppers found that high storage temperature strongly increases oxygen transfer at the glass-cork interface. Storage conditions did not modify the oxygen diffusion coefficient of the cork stopper alone. Temperature did affect the total oxygen transfer, which includes transfer at the glass-cork interface. At 35°C, a temperature easily reached during bottle shipping, total oxygen transfer did not increase significantly for up to 9 months. Beyond that duration, a significant transfer at the glass-cork interface started to occur, according to Chanut et al. At 50°C, this shift already occurs within the first 3 months of storage, Chanut et al. reports. Chanut et al. suggests two candidates: a partial melting of the surface treatment agent on the cork, or a modification of the stopper's mechanical properties.

Does bottle orientation matter for wine storage?

For most still wines, storing bottles on their side is a common practice. Most wine racks suit this orientation. The thinking behind this is simple. Constant contact with the wine keeps the cork moist. Some wineries package their wines upside down for much the same reason. Research in the late 1990s suggested that the ideal orientation for wine bottles is at a slight angle, rather than completely horizontal. That angle lets the cork maintain partial contact with the wine while keeping the ullage air bubble at the top. The argument: this orientation allows a slower and more gradual oxidation and maturation process.

However, for sparkling wines like Champagne, the recommendations differ. A common recommendation to store Champagne upright rather than lying on its side. The internal pressure from the trapped carbonic gas provides enough humidity and protection from oxygen. Caterer Magazine claims that the Comité Interprofessionnel du Vin de Champagne (CIVC) found Champagne stored on its side aged more quickly. The Comité Champagne website states that "Bottles can be stored upright or on their sides, in a cool place, at a constant temperature of between 10 and 15°C". The Comité Champagne further advises that Champagne "will, however, keep well for several years if stored on its side in a cool, dark, draft-free place, following the three golden rules of Champagne storage: Constant, low ambient temperature (around 10 °C/50 °F) Generous humidity No direct exposure to sunlight, noise or excessive vibration."

A study by Chanut et al. (2023) tested microagglomerated cork stoppers with model wine in two positions. One was vertical, with the cork in contact with the vapor phase; the other horizontal, with the cork in contact with the liquid phase. Neither position influenced oxygen transfer through the bottleneck-cork system. The study concluded that storage position had no significant influence on oxygen transfer. That held through the cork and at the glass-cork interface, over a 24-month aging period at 20°C.

What role does light play in wine spoilage?

Three factors have the most direct impact on a wine's condition. Light is one, alongside humidity and temperature. Direct sunlight or incandescent light can adversely react with phenolic compounds in wine and create "wine faults." Light from sunlight, fluorescent artificial lights, or any other source can change a wine's flavor and aroma.

AWRI Technical Note TN09 explains that light exposure can affect the taste of a wine. The mechanism is the production of volatile sulfur compounds, known as ‘lightstruck’ flavour. Dozon and Noble (1989) bottled still and sparkling white wines in green glass. Lightstruck flavour developed after 31.1 hours and 18 hours of exposure to fluorescent lamps, respectively. The same wines in clear glass fared worse, Dozon and Noble (1989) reported. A statistically significant level of off-flavour developed after only 3.3 hours and 3.4 hours, respectively. Direct sunlight provides 4286 times the amount of UV-A radiation as fluorescent lamps. That figure comes from Gordon Watson, Gordon Watson and Associates, pers. comm. Bottled wine meets sunlight in retail window displays. AWRI Technical Note TN09 suggests that this is more deleterious to wine quality than exposure to electric lighting systems.

To protect wine from light damage:

• Tinted Bottles: Light-bodied white wines run the greatest risk from light exposure. Tinted wine bottles offer them some protection. Wines packaged in clear, light green, and blue colored bottles are the most vulnerable and may need extra precautions for storage. Rankine (1989) indicates that amber glass is most effective in excluding wavelengths below about 450 nm, according to the AWRI Technical Note TN09.
• Protective Packaging: we advise storing cellar wines in corrugated boxes or wooden crates to protect them from direct light.

How does humidity affect wine and its closure?

Humidity is a critical factor for wines sealed with natural corks, and for those alone. Cork enclosures need some humidity to keep from drying out. Even in bottles lying on their sides, one side of the cork still meets air. Should the cork begin to dry out, it can allow oxygen to enter the bottle. That oxygen fills the ullage space and can spoil or oxidize the wine.

Excessive humidity poses its own risks. It can damage wine labels. Label damage may hinder identification or hurt potential resale value. Wine experts such as Jancis Robinson note the 75% figure often cited as ideal. They also note that there is very little significant research to definitively establish an optimal range. Tom Stevenson recommends against keeping wine in a refrigerator, because the refrigeration process often includes dehumidifying, which can quickly dry out corks.

There is some debate on the importance of humidity. M. Kramer, in The Wine Spectator, cites a French study. It claimed that the relative humidity within a bottle stays at 100%. That holds regardless of the closure used or the orientation of the bottle. Conversely, Alexis Lichine contends that low humidity can still hurt premium wine quality. The cork risks drying out. He recommends spreading half an inch of gravel on the floor of a wine cellar. Sprinkling it with some water from time to time maintains optimal humidity.

The Comité Champagne recommends that for Champagne bottles, humidity must be high and constant, between 60% and 80%.

What about vibrations during storage?

Anecdotal information suggests that vibrations contribute to accelerated ageing with adverse effects. This remains a research area with relatively little data. One study found that vibrations of different frequencies each have a distinct effect on wine chemistry. The study concluded that "Vibration could be used to accelerate the ageing of wine, but in most cases, this may lead to negative effects on wine quality. Therefore, to store red wines with limited changes in physicochemical properties, vibrations should be minimized." The Comité Champagne also advises protecting bottles from vibrations.

Ideal Storage Conditions for Your Collection

Consistent, appropriate storage conditions are the key to preserving your wine. The AWRI recommends storing bottled wine with the cork in contact with the wine, in a cool (15-20°C), dry location (Amon and Simpson 1986). The Comité Champagne recommends a constant temperature of between 10 and 15°C for Champagne. It also calls for high and constant humidity between 60% and 80%, and protection from light, vibrations, and odours.

Condition	Still Wine (General)	Champagne
Temperature	Constant 50-59 °F (10-15 °C)	Constant 10-15 °C (Comité Champagne)
Humidity	Some degree required to prevent cork drying; J. Robinson notes 75% often cited as ideal	High and constant, 60-80% (Comité Champagne)
Light	Protected from direct sunlight or incandescent light; Store in corrugated boxes or wooden crates	Protected from light (Comité Champagne)
Vibration	Should be minimized, especially for red wines	Protected from vibrations (Comité Champagne)
Orientation	On side, or slight angle	Upright or on sides (Comité Champagne)

For a fuller approach to protecting your collection, read our guide on how to store wine. If you are looking to sell, condition drives value. That is the heart of fine wine investment. Physical damage, such as a low fill level, can impact a wine's marketability.

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