Wine can be mysterious. It evolves in the bottle, reacts to temperature and even affects the way we sleep.
Here are clear answers to three commonly asked wine questions.
#1 Can Wine Turn?
Understanding Wine Oxidation
Have you ever wondered whether wine can “turn”? The answer is yes, although turn is not a technical winemaking term.
Wine can deteriorate through oxidation, microbial spoilage, excessive heat or simply by ageing beyond its best drinking window. These processes are different, but they can all leave a wine tasting tired, flat or unpleasant.
Oxidation occurs when wine is exposed to too much oxygen. Small and controlled amounts of oxygen can play a valuable role in winemaking and maturation, but excessive exposure eventually causes a wine to lose its freshness, fruit and vibrancy.
What Do Sulphites Do?
Sulphur dioxide, commonly referred to as sulphites, helps protect wine against oxidation and unwanted microbial activity. Small amounts can occur naturally during fermentation, and winemakers may add carefully controlled quantities to preserve the wine.
This means that even a wine made without added sulphur dioxide may still contain naturally occurring sulphites. The terms natural wine and preservative-free wine do not necessarily mean that a wine contains absolutely no sulphites.
Modern refrigeration, inert gas and careful sulphur dioxide management have made serious oxidation faults less common than they once were.
How Can You Recognise an Oxidised Wine?
An oxidised white wine may become deeper gold, amber or brown. Its fresh fruit aromas can be replaced by characters resembling bruised apple, nuts or sherry.
An oxidised red wine may develop a brick-orange or brown colour. It can lose its fresh berry and floral aromas and begin to taste flat, tired or dried out.
However, a strong vinegar aroma is not simply a sign of oxidation. It is more commonly associated with excessive volatile acidity, which can develop through microbial activity.
It is also important to remember that oxidative characters are not always faults. They are deliberately encouraged in wines such as Madeira and some styles of sherry. In those wines, nutty and developed flavours are part of the intended style.
Is an Oxidised Wine Dangerous?
An oxidised wine is not normally dangerous to drink, but it may no longer provide an enjoyable tasting experience.
If the wine smells strongly abnormal, the bottle or closure is damaged, or there is any concern about contamination, it is sensible not to drink it.
What Is a Corked Wine?
A corked wine is different from an oxidised wine.
Cork taint is most commonly associated with a compound called TCA. It may originate from a contaminated cork, but related contamination can also occur in barrels, wooden structures or other parts of a winery environment.
A corked wine commonly smells like damp cardboard, a mouldy cellar or wet newspaper. At lower levels, there may be no obvious mouldy smell; the wine may simply seem muted, with very little fruit or aroma.
Burnt rubber, smoke and camphor are not the classic signs of cork taint and may indicate other wine faults or aroma compounds.
Cork taint is unpleasant rather than normally harmful. It also does not necessarily indicate careless winemaking. Even a meticulously produced wine can occasionally be affected by a contaminated closure or cellar material.
#2 Can Wine Freeze?
The Cold, Hard Truth
Have you ever placed a bottle of wine in the freezer for a quick chill, forgotten about it and returned to find it frozen?
Wine can indeed freeze.
Because wine contains alcohol, sugar, acids and other dissolved compounds, it freezes at a lower temperature than water. The precise freezing point depends on the wine’s alcohol and sugar content, but an ordinary household freezer is cold enough to freeze most table wines.
The wine industry can even use carefully controlled partial freezing to remove water and concentrate wine, a process known as cryoconcentration.
What Happens to the Bottle?
Water expands as it freezes. As ice forms inside a wine bottle, the increased pressure may:
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push the cork out;
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compromise the seal;
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cause the bottle to leak; or
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crack or break the glass.
A screw cap may also be damaged or forced out of position.
Can Frozen Wine Be Saved?
If the bottle remains completely intact, allow the wine to thaw slowly in the refrigerator.
Once thawed, examine the bottle and taste the wine. Freezing does not automatically make wine unsafe, but it may alter its texture, aromas or appearance. Tartrate crystals or other harmless deposits may also become visible.
If the cork has moved or the seal has been compromised, oxygen may have entered the bottle. The wine may still be usable, but it should be opened and assessed promptly rather than returned to long-term storage.
If the glass has cracked or broken, discard the wine. Even if the damage appears minor, tiny fragments of glass may be present.
What About Sparkling Wine?
Sparkling wine requires particular caution because the bottle is already under considerable internal pressure.
Freezing causes the liquid to expand, which may force out the closure or break the bottle. Champagne and other sparkling wines should therefore not be left in the freezer.
A Safer Way to Chill Wine Quickly
The safest quick-chilling method is to place the bottle in an ice bucket containing both ice and water. Water fills the gaps around the bottle and transfers heat more efficiently than ice alone.
Adding salt can reduce the temperature of the ice bath further, but the bottle should still be monitored closely.
#3 Can Wine Prevent Sleep?
Can Wine Disrupt Sleep?
Wine may make you feel sleepy, but that does not necessarily mean it will help you sleep well.
Alcohol initially acts as a sedative and may reduce the time it takes to fall asleep. As the alcohol is metabolised, however, sleep can become lighter and more fragmented, particularly during the second half of the night.
Alcohol can alter normal sleep architecture, reduce or delay REM sleep and increase the likelihood of waking during the night. It may also worsen snoring and obstructive sleep apnoea by relaxing the muscles around the airway.
Is Adrenaline Responsible?
The original explanation that alcohol triggers the release of large amounts of adrenaline is too simplistic.
Alcohol affects several neurotransmitters and biological systems involved in sleep and wakefulness. As its sedative effect wears off, the brain can become more active and sleep can become disrupted. This is sometimes described as a rebound effect, but it cannot be attributed solely to adrenaline.
Alcohol may also influence circadian rhythms and melatonin signalling, although these are only part of the broader effect alcohol has on sleep.
Does Everyone React in the Same Way?
The effect varies considerably between individuals.
The amount consumed, the time of consumption, personal metabolism, medications, migraine susceptibility, hormonal changes and existing sleep conditions may all influence the result.
Some people notice disrupted sleep after only one or two glasses, while others are more affected after consuming a greater amount.
Does Eating Help?
Eating before or while drinking can slow the absorption of alcohol and reduce how quickly the blood alcohol level rises. It does not, however, prevent alcohol from affecting sleep once it has been absorbed.
Similarly, drinking water can support hydration but cannot neutralise alcohol or guarantee uninterrupted sleep.
There is no reliable scientific evidence that taking a spoonful of olive oil before drinking will prevent alcohol-related sleep disruption.
How Can You Reduce the Effect on Sleep?
The most reliable approach is to consume less alcohol and avoid drinking close to bedtime.
Drinking wine earlier in the evening, having it with food and alternating it with water may help some people, but they do not completely remove alcohol’s effect on sleep.
Anyone who experiences regular insomnia, loud snoring, breathing interruptions or persistent daytime exhaustion should discuss those symptoms with a healthcare professional.
The Final Word
Wine can oxidise, freeze and disrupt sleep, but each happens for a different reason.
Proper storage can help protect wine from excessive oxygen and temperature changes. Moderate consumption and thoughtful timing can also reduce the likelihood that an evening glass will interfere with a good night’s rest.