Wine Troubles? Here’s How to Tell When Your Bottle Is Off.

More often than not, in my missives, I write about how wonderful wine is and the pleasure it can bring (if you drink it from the correct glass!).

But, very occasionally, you will come across a bottle that isn’t quite what you were expecting. There are a number of reasons why a wine can be “bad” (by this I mean actually off, rather than you just not being keen on the taste) so I thought I’d go over the more common issues you may encounter.

Wine, whilst often seen as a symbol of sophistication and elegance, requires careful handling and storage. However, even with the utmost care, sometimes things go wrong, and the result is a flawed or faulty wine.

Understanding wine faults is essential for anyone who enjoys wine, whether you're a casual sipper or a seasoned connoisseur.

Cork Taint (TCA)

What Is It? :

Cork taint is one of the most dreaded issues in the wine world, and it's often the culprit behind an otherwise perfect bottle turning into a disappointment. The primary cause of cork taint is the presence of a chemical compound called 2,4,6-trichloroanisole, commonly abbreviated as TCA. This compound is typically formed when naturally occurring fungi in the cork come into contact with certain chlorine-based chemicals. These chemicals might be used during the cork's production process, particularly in the bleaching or sterilisation stages.

TCA is a potent compound, and even minute quantities can lead to significant wine spoilage. It’s important to note that while cork taint is mostly associated with actual corks, it can also occur in wines sealed with screw caps or synthetic corks, although this is far less common. This is because TCA can be introduced at various stages of the winemaking process, not just through the cork itself.

How TCA Forms:

TCA formation is a complex chemical reaction. When natural fungi present in the cork come into contact with chlorophenols - compounds that can be found in pesticides, wood preservatives, or even in some cleaning agents, all commonly used in and around vineyards - TCA can be produced. Chlorophenols can also be present in winery equipment or barrels, further increasing the risk of contamination.

Once TCA has formed, it is absorbed into the cork and then transferred to the wine. The process is insidious because TCA is extremely potent; it can affect wine even at concentrations as low as a few parts per trillion. This means that a wine may smell and taste "off" even if the levels of TCA are too low to be detected through analytical testing.

How to Identify It:

Identifying a corked wine can sometimes be challenging. The characteristic signs include a distinctive musty aroma that is often described as resembling wet cardboard, a damp basement, or a mouldy newspaper. In some cases, the smell may be more subtle, making the wine seem just a bit "off" rather than outright spoiled.

On the palate, a corked wine will typically taste flat and muted. The vibrant fruit flavours that should characterise the wine will be suppressed, and the wine may also lack its usual complexity and finish. Instead of the expected bouquet of aromas and flavours, a corked wine often leaves an impression of being stale. This can be especially disappointing when the wine in question is one that’s known for its expressive character.

It's important to distinguish between cork taint and other issues that might affect a wine's aroma or flavour. For example, some older wines may naturally develop earthy or musty notes that are not related to TCA, but are instead a result of bottle aging. The key difference is that cork taint generally strips the wine of its intended flavours, leaving it lifeless.

What to Do:

If you encounter a corked wine, there’s unfortunately no way to remedy the situation. It is a fault that cannot be corrected once it has affected the wine. However, all is not lost. Most retailers and wine producers understand the frustration that comes with discovering a corked bottle and are usually willing to offer a replacement or refund.

Here’s what you should do if you suspect your wine is corked:

1. Verify the Fault: Before jumping to conclusions, take a moment to assess whether the wine is truly corked. Sometimes, a wine may need a bit of air to open up, especially if it’s been stored in a bottle for a long time. However, if the musty, wet cardboard smell persists and the wine tastes flat, it’s probably corked.
2. Retain the Bottle and Cork: If you’re planning to return the wine, make sure to keep the bottle, cork, and any remaining wine intact. Many retailers and wineries will ask for these items when processing a return or exchange.
3. Contact the Retailer or Producer: Most reputable wine shops and producers will replace corked bottles without much hassle. If you purchased the wine at a store, take it back with your receipt. If it was purchased directly from a winery or online, contact their customer service department for instructions.
4. Avoid Future Cork Taint: While you can’t control whether a bottle will be corked, you can minimize the chances by purchasing from producers known for quality control. Some wineries have even transitioned to alternative closures, such as screw caps or synthetic corks, to reduce the risk of cork taint.

Why Cork Taint Matters:

Cork taint may seem like a minor inconvenience, but it’s a significant issue for the wine industry. It’s estimated that between 1-5% of all wines sealed with natural cork may be affected by TCA, which translates to millions of bottles each year. This not only represents a financial loss for producers and retailers but also risks disappointing consumers who might be experiencing a particular wine or brand for the first time.

Moreover, cork taint has led to increased interest in alternative wine closures, such as screw caps and synthetic corks, which are not susceptible to TCA. While these closures have their own sets of advantages and disadvantages, the desire to avoid cork taint has been a major factor in their growing popularity.

Oxidation

What Is It? :

Oxidation is one of the most common faults that can affect wine, and it occurs when the wine is exposed to oxygen for an extended period. While a certain amount of oxygen exposure is beneficial - it's why we decant or swirl wine in the glass - too much oxygen can lead to the breakdown of the wine's chemical compounds, resulting in undesirable changes in aroma, flavour, and colour.

During the winemaking process, careful measures are taken to manage the amount of oxygen that comes into contact with the wine. For example, many winemakers will use inert gases like nitrogen or carbon dioxide to protect the wine from oxidation during bottling and aging. However, if there’s a lapse in this control, or if the wine is exposed to air due to a faulty closure, oxidation can occur.

How It Occurs:

Oxidation happens when wine is exposed to air, oxygen reacts with phenolic compounds in the wine, leading to the formation of acetaldehyde and other oxidative compounds. Over time, these reactions can result in a loss of freshness, colour changes, and the development of off-flavours.

Several factors can lead to oxidation:

1. Faulty Closures: If a cork or other closure fails to seal the bottle properly, oxygen can seep in, gradually oxidising the wine. This is more common in older bottles where the cork may have deteriorated, but it can also happen in newer bottles if the cork is of poor quality or was not inserted correctly.
2. Improper Storage: Storing wine upright for extended periods can cause the cork to dry out, allowing air to enter the bottle. Additionally, wines stored in excessively warm or fluctuating temperatures are more prone to oxidation, as heat accelerates the chemical reactions that lead to spoilage.
3. Winemaking Errors: During the winemaking process, improper handling, such as excessive racking (transferring wine between containers) or not topping off barrels to minimize air space, can introduce too much oxygen. Additionally, wines that are not adequately protected with sulfites (which act as antioxidants) are more vulnerable to oxidation.
4. Bottling Issues: During bottling, if there’s too much headspace (air between the wine and the closure) or if inert gases aren’t used properly, the wine can begin to oxidise even before it’s sealed.

How to Identify It:

Oxidised wine is relatively easy to identify, when you know what to look for. The most noticeable sign of oxidation is a change in colour. For white wines, this typically means a shift from a bright, clear hue to a darker, more amber or brownish shade. Red wines may take on a brick-red or tawny colour rather than their usual vibrant red or purple tones.

The aromas and flavours of oxidised wine are equally telling. Fresh fruit aromas are replaced by more muted or unpleasant scents. You might notice aromas reminiscent of sherry, nuts, or even vinegar. On the palate, the wine will likely taste flat and lack the vibrant, fruity characteristics it should have. Instead, it might taste stale, with nutty, caramelized, or even sour notes, which are far from the intended profile of the wine.

It’s important to differentiate between intentional oxidation, as seen in wines like Sherry, Madeira, or certain styles of Chardonnay, and unintentional oxidation, which is considered a fault. In wines where oxidation is part of the winemaking style, the nutty, sherry-like qualities are desirable and balanced with other complex flavours. In other wines, these characteristics are unwanted and indicate spoilage.

What to Do:

Once a wine has oxidised, there’s no way to reverse the damage. The wine has permanently lost its original character and freshness. However, all is not lost if you find yourself with a dodgy bottle:

1. Return the Wine: If you discover that a newly opened bottle of wine is oxidised, many retailers and producers will allow you to return it for a replacement or refund. Be sure to keep the bottle, closure, and any remaining wine intact.
2. Assess Older Wines Carefully: When opening older wines, especially those that have been stored for many years, it’s not uncommon to encounter some level of oxidation. However, slight oxidation in well-aged wines can add complexity and isn’t always considered a fault. It’s when the oxidation dominates the wine’s profile that it becomes a problem.
3. Use a Wine Preservation System: To prevent oxidation after opening a bottle, consider investing in a wine preservation system. These systems, like the ……
4. Proper Storage: Always store wine in a cool, dark place with a consistent temperature. Wine should be stored on its side to keep the cork moist, which helps maintain a tight seal. Avoid placing bottles in areas where they might be exposed to light, heat, or vibration, all of which can accelerate oxidation.

Why Oxidation Matters:

Oxidation is a problem because it fundamentally changes the wine, stripping it of the qualities that make it enjoyable. Freshness, fruitiness, and complexity can all be lost, leaving behind a dull, lifeless drink. For wine producers, oxidation represents a significant risk, as even a small amount of oxygen exposure can spoil an entire batch.

For consumers, oxidation can be particularly frustrating, especially when it affects a bottle that has been carefully stored or is from a highly anticipated vintage. It’s one of the reasons why understanding proper wine storage and handling is so important, as even a small mistake can lead to significant disappointment.

On a positive note, oxidation has driven innovation in packaging and closure technologies. Screw caps, for example, have become more popular in part because they offer a more airtight seal compared to natural cork, thus reducing the risk of oxidation. While there is ongoing debate in the wine world about the best closures for aging wine, the push to prevent oxidation remains a central concern.

Volatile Acidity (VA)

What Is It? :

Volatile acidity (VA) refers to the presence of volatile acids in wine, primarily acetic acid and its esters, such as ethyl acetate. These compounds can be naturally present in small quantities in all wines and contribute to its complexity. However, when these compounds exceed acceptable levels, they become a significant fault, giving the wine an unpleasant, sharp taste and smell.

Causes of Volatile Acidity:

1. Bacterial Contamination: The most common cause of high VA in wine is the activity of acetic acid bacteria (Acetobacter) during or after fermentation. These bacteria convert alcohol into acetic acid when oxygen is present, which can occur if the wine is exposed to air during production, storage, or bottling.
2. Yeast Strains: Certain wild yeast strains, such as Brettanomyces, can also contribute to higher levels of VA. While some winemakers may tolerate or even encourage a slight Brett character for added complexity, excessive activity leads to an overproduction of volatile acids.
3. Poor Sanitation: Improper sanitation in the winery can introduce or spread acetic acid bacteria, increasing the likelihood of VA. Contaminated barrels, unclean equipment, or improperly stored wine can all contribute.
4. Oxygen Exposure: Oxygen plays a crucial role in the formation of acetic acid. Wines that are inadequately protected from oxygen during aging, bottling, or storage are more likely to develop higher levels of VA. This is particularly a risk in wines stored in barrels that are not topped up regularly to replace evaporated wine.
5. Residual Sugar: Wines with residual sugar are more susceptible to bacterial contamination if proper sulphite levels are not maintained. The bacteria can feed on the sugars, producing acetic acid as a byproduct.

How to Identify It:

High volatile acidity is relatively easy to detect once you know what to look for:

1. Aroma: The most immediate giveaway of escess VA is a strong, sharp aroma reminiscent of vinegar. You may also detect the scent of nail polish remover or paint thinner, which comes from the presence of ethyl acetate. While some wines might have a faint hint of these aromas without being faulty, an overpowering scent usually indicates an excessive level of VA.
2. Taste: On the palate, wines with high VA will taste sharp, sour, and acidic, with a harshness that can overwhelm the wine’s other flavours. The acidity can also leave a burning sensation in the throat, similar to what you might experience from a strong vinegar.
3. Balance: VA can completely disrupt the balance of a wine. Even if a wine has pleasant flavours or aromas, excessive VA can mask them, making the wine feel disjointed or inharmonious.

What to Do:

Unfortunately, once a wine has developed excessive volatile acidity, there is no way to reverse the fault. However, there are steps you can take if you encounter a wine with high VA:

1. Evaluate Your Tolerance: Some wine drinkers may find that they are more sensitive to VA than others. If you are unsure whether the VA level is unacceptable, consider getting a second opinion. In some rustic or natural wines, a slight VA might be tolerated or even appreciated for its contribution to complexity.
2. Return the Wine: If you find the VA level too high for your liking, and especially if you believe the wine is faulty, consider returning it. Most reputable wine retailers and producers will allow you to return a bottle if it is flawed, particularly if you have kept the receipt and bottle intact.
3. Store Wine Properly: To minimize the risk of VA in your own collection, ensure that wines are stored in a cool, stable environment with minimal exposure to oxygen. This means keeping bottles on their sides to keep the corks moist, avoiding temperature fluctuations, and consuming opened bottles promptly or using a wine preservation system.

Why Volatile Acidity Matters:

Volatile acidity is a crucial aspect of wine chemistry that winemakers must carefully manage. While a tiny amount of VA can add complexity and intrigue to certain wines, it is generally viewed as a fault when it exceeds the threshold of sensory perception. High VA can ruin an otherwise beautiful wine, turning what should be a pleasurable experience into a disappointing one.

For winemakers, controlling VA involves careful monitoring of oxygen levels, maintaining rigorous sanitation standards, and using appropriate sulphur dioxide (SO2) levels to inhibit bacterial growth. For wine enthusiasts, understanding VA helps in recognising when a wine is flawed and when it might be time to return a bottle or explore a different selection.

Brettanomyces (Brett)

What Is It? :

Brettanomyces, commonly referred to as "Brett," is a wild yeast that can significantly influence the aroma and flavour profile of wine. Unlike Saccharomyces cerevisiae, the yeast typically used in winemaking for fermentation, Brettanomyces is often considered a spoilage organism. However, its impact on wine can be complex and is sometimes a matter of debate among wine lovers and producers.

Causes and Characteristics:

1. Fermentation and Aging: Brettanomyces can be introduced into wine during fermentation or aging, particularly in wooden barrels that are difficult to sanitise completely. It thrives in environments where oxygen is present, but it can also survive in low-oxygen conditions. Brett can ferment sugars and produce several byproducts, including volatile phenols, which contribute to its distinctive aroma and flavour profile.
2. Volatile Phenols: The most notable compounds produced by Brett are 4-ethylphenol and 4-ethylguaiacol. These are responsible for the characteristic aromas associated with Brett, such as barnyard, wet animal and medicinal notes. At low levels, these aromas can add a layer of complexity, giving the wine an earthy, rustic quality. However, when Brett is present in high concentrations, these flavours can dominate, overwhelming the wine's fruit and other desirable characteristics.
3. Winemaking Practices: Brettanomyces contamination can result from poor sanitation practices, the use of old or poorly maintained barrels, or the use of musts with high pH levels. Some winemakers may allow for a controlled amount of Brett to develop as part of their winemaking style, particularly in certain traditional or natural wines where a bit of "funk" is desired. However, this is risky, as Brett is difficult to control once it takes hold.

How to Identify It:

Identifying Brett in wine can be both straightforward and challenging, depending on its concentration and the wine's other characteristics:

1. Aromas: The most common descriptors for Brett aromas are barnyard, horse saddle, wet dog, leather, and medicinal scents. These smells are the result of the volatile phenols produced by the yeast. In low concentrations, Brett might present as a subtle earthy or spicy note, but as the concentration increases, the aromas become more pungent and unpleasant.
2. Flavours: On the palate, Brett can impart similar earthy, gamey, or medicinal flavours. It can also cause the wine to taste somewhat metallic or bitter. As Brett increases, it can strip the wine of its fruitiness and freshness, leaving it tasting flat and unbalanced.
3. Mouthfeel: Brett can also affect the mouthfeel of the wine, sometimes creating a drying or astringent sensation that further detracts from the wine's appeal.

What to Do:

Once Brettanomyces is present in wine, it cannot be removed or corrected. Here’s how to handle a wine with Brett:

1. Evaluate Your Preference: Some wine enthusiasts enjoy the complexity that a hint of Brett can add to a wine, particularly in certain styles like Rhône reds or traditional Belgian beers. If the Brett character is mild and integrates well with the wine's other flavours, it may not be considered a fault by some drinkers. However, if the Brett aromas and flavours are overpowering, most people will find the wine unpleasant.
2. Decanting: In some cases, decanting the wine or allowing it to breathe for a while may help to diminish the impact of Brett by letting some of the volatile compounds dissipate. However, this is not always effective, especially if the Brett is present at high levels.
3. Return the Wine: If you purchased a bottle that is heavily Brett-affected and it was not advertised or intended to be that way, most wine retailers or producers will allow you to return it. This is especially true if the wine is meant to be a clean, fruit-driven style where Brett would be considered a flaw.
4. Preventing Brett: For winemakers, preventing Brett contamination involves rigorous sanitation, careful monitoring of wine during aging, and possibly the use of sulphites to inhibit the growth of Brettanomyces. For consumers, knowing the reputation of a winery and its practices can help avoid inadvertently purchasing wines with unwanted Brett character.

Why Brett Matters:

Brettanomyces is a polarising topic in the wine world. While some traditional wine styles embrace a touch of Brett for its ability to add complexity, high levels of Brett can render a wine unpleasant and unbalanced, masking its fruit and other desirable qualities. Understanding Brett helps wine enthusiasts appreciate the fine line between complexity and fault, and it underscores the importance of proper winemaking practices to maintain wine quality.

Reduction

What Is It? :

Reduction in wine refers to a state where the wine is deprived of oxygen, leading to the development of sulphur compounds that can impart unpleasant aromas and flavours. This condition is essentially the opposite of oxidation and can occur during winemaking, particularly in wines aged in environments with little exposure to air, such as stainless steel tanks or under screw caps.

Causes and Characteristics:

1. Lack of Oxygen: Reduction occurs when wine is stored or aged in conditions with minimal oxygen exposure. While some level of reduction is normal and even desirable during the aging process (as it can help preserve the wine's freshness), excessive reduction leads to the formation of undesirable sulphur compounds like hydrogen sulphide (H2S) and mercaptans.
2. Sulphur Compounds: The primary culprits behind reduction are sulphur compounds, which can give off a range of unpleasant aromas. Hydrogen sulphide smells like rotten eggs, while mercaptans can produce odours reminiscent of garlic, onions, or even burnt rubber.
3. Winemaking Practices: Reduction can be influenced by winemaking choices, such as the use of sulphur dioxide (SO2) to protect the wine from oxidation or microbial spoilage. While SO2 is a crucial preservative, excessive use or inadequate management of oxygen during winemaking can lead to a reduced wine. Wines aged in airtight conditions, such as in screw-capped bottles or stainless steel tanks, are more susceptible to reduction, particularly if the wine was bottled with high levels of dissolved sulphur compounds.

How to Identify It:

Reduced wines are often easy to identify due to their distinctive and unpleasant aromas:

1. Aromas: The most common indicators of reduction are aromas of rotten eggs, burnt rubber, garlic, cabbage, or struck matches. These odours result from the sulphur compounds produced in the absence of oxygen. In some cases, the reduction may manifest as a slight stink that dissipates with time, while in others, the smell can be overwhelming and persistent.
2. Taste: On the palate, a reduced wine might taste dull or flat, lacking the vibrant fruit flavours and freshness expected. The sulphur compounds can also impart a bitterness or metallic taste, further detracting from the wine's overall balance and appeal.

What to Do:

If you encounter a reduced wine, there are a few steps you can take to potentially improve its drinkability:

1. Decanting or Aeration: Mild reduction can often be corrected by exposing the wine to air. Decanting the wine, swirling it vigorously in the glass, or using a wine aerator can help to dissipate some of the sulphur compounds, improving the wine's aroma and flavour.
2. Copper Coin Method: In cases of slight reduction, some wine enthusiasts use a copper coin (penny) trick. Dropping a clean copper coin into the glass can bind with the sulphur compounds and neutralize the odours. This method works best with mild cases of reduction and is more of a stopgap than a solution.
3. Preventing Reduction: For winemakers, preventing excessive reduction involves careful management of oxygen during winemaking, especially during aging and bottling. For consumers, being aware of the types of closures and aging methods used by a winery can help in selecting wines less prone to reduction.

Why Reduction Matters:

Reduction, like Brettanomyces, is another example of how winemaking techniques and storage conditions can significantly impact the final product. While a touch of reduction can sometimes add complexity to a wine, excessive reduction is generally viewed as a flaw that detracts from the wine's enjoyment. Understanding reduction helps wine enthusiasts recognize when a wine might benefit from a bit of air or when it’s best to move on to another bottle.

Heat Damage (Maderisation)

What Is It? :

Heat damage, also known as maderisation, occurs when wine is exposed to excessive heat, leading to premature aging and degradation of its intended characteristics. This process results from the wine being stored or transported in conditions where temperatures are too high or fluctuate dramatically. Maderisation takes its name from the Madeira wine style, which traditionally undergoes controlled heat aging to develop its unique flavours, but in this context, it refers to unintended heat damage.

Causes and Characteristics:

1. High Temperatures: Exposure to high temperatures accelerates the chemical reactions in wine that cause it to age. This can happen if wine is left in a hot car, stored in an overheated warehouse, or subjected to significant temperature fluctuations.
2. Premature Aging: When a wine is subjected to heat damage, it can undergo a form of accelerated aging. The heat causes the wine's volatile compounds to evaporate and its chemical structure to break down, leading to a loss of freshness and vibrancy. The wine may develop flavours and aromas that are typically associated with older wines, but without the complexity and balance that comes with proper aging.
3. Flavour and Aroma Changes: Heat damage often results in a wine that tastes "cooked" or "stewed." You might detect flavours of overripe or caramelized fruit, and the wine can develop an overly sweet, burnt sugar, or toasty profile. The aroma can also become more subdued and flat, losing its original fruit and floral notes.
4. Colour Changes: Heat-damaged wine may exhibit darker hues compared to its usual appearance. For white wines, this might mean a shift from pale yellow to a deeper, more amber colour. Red wines might take on a brownish or brick-red tint rather than their usual vibrant reds.

How to Identify It:

1. Aromas: Heat-damaged wine often smells like cooked fruit, burnt sugar, or caramel. You might also notice a lack of the fresh, bright aromas typical of a well-preserved wine.
2. Flavours: On the palate, the wine may taste overly sweet or like stewed fruit. It can also have a flat, dull quality, lacking the intended freshness and complexity. The wine might feel heavy or syrupy, without the balanced acidity and vibrant fruit flavours that should be present.
3. Colour: Check the colour of the wine. If a white wine has darkened significantly or a red wine appears more brownish than usual, heat damage could be the cause.

What to Do:

1. Return or Exchange: If you find that a bottle has been heat-damaged, it’s best to return it to the retailer or producer. Many wine merchants will allow exchanges or refunds for bottles affected by heat damage, especially if the issue was caused by improper handling during shipping.
2. Proper Storage: To prevent heat damage, always store wine in a cool, dark place with a stable temperature. Ideally, wine should be kept at a temperature around 55°F (13°C) and stored on its side to keep the cork moist. Avoid storing wine in areas prone to temperature fluctuations, such as near heat sources or in direct sunlight.
3. Temperature Monitoring: If you’re purchasing wine online or having it shipped, choose a retailer known for good shipping practices and consider investing in a temperature-controlled delivery service, especially for high-value bottles.

Why Heat Damage Matters:

Heat damage is a significant issue for wine quality because it can drastically alter the wine's flavour, aroma, and appearance. The effects are irreversible, and the resulting wine may no longer reflect the intended style or quality. Understanding heat damage helps consumers and retailers alike ensure that wine is stored and transported properly to maintain its optimal condition.

Secondary Fermentation

What Is It? :

Secondary fermentation occurs when residual sugars in wine re-ferment after the initial fermentation process is complete. This is typically a concern in still wines, where additional fermentation is not intended after bottling. This condition often results from improper filtration or bottling practices, allowing yeast or other microorganisms to continue fermenting the sugars left in the wine.

Causes and Characteristics:

1. Residual Sugars: If a wine has residual sugars that were not fully fermented or removed, these sugars can serve as food for yeast or bacteria. If these micro-organisms are present, they can begin a secondary fermentation in the bottle.
2. Improper Filtration: Inadequate filtration or stabilisation of the wine before bottling can leave behind yeast or other micro-organisms capable of fermenting sugars. This can be due to issues in the winemaking process, such as not using enough sulphur dioxide to inhibit microbial growth.
3. Bottling Practices: Secondary fermentation is more common in still wines that have been bottled without thorough filtration. It can also occur if the bottling process allowed for the introduction of new yeast or if the wine was bottled with excessive headspace (air).

How to Identify It:

1. Fizz or Bubbles: The most noticeable sign of secondary fermentation is unexpected fizz or bubbles in a still wine. While sparkling wines are intended to be effervescent, still wines should not have carbonation.
2. Aromas: You might detect aromas reminiscent of sparkling wine, such as yeast or bread dough. These are indicative of ongoing fermentation.
3. Flavors: Secondary fermentation can make the wine taste off-balance, with flavours that might include a slight sourness or tang. The wine might also taste yeasty or bready, which is unusual for a still wine.
4. Appearance: In some cases, you might see sediment in the bottle, which is the result of the fermentation process. This sediment can be a sign that the wine underwent secondary fermentation.

What to Do:

1. Return the Wine: If you encounter a still wine with signs of secondary fermentation, it’s best to return the bottle to the retailer or producer. Secondary fermentation in a still wine is typically considered a fault and is not how the wine was intended to be enjoyed.
2. Enjoy It If You Like: Some consumers may find the unexpected carbonation and yeastiness interesting or enjoyable. If the wine’s flavour profile is not completely unpleasant, you might choose to drink it, though it’s generally not what the producer intended.
3. Check Bottling Practices: For winemakers, preventing secondary fermentation involves ensuring thorough filtration and stabilization of the wine before bottling. Properly managing residual sugar levels and using appropriate sulphur dioxide levels can help avoid this issue.

Why Secondary Fermentation Matters:

Secondary fermentation is significant because it affects the wine's intended style and quality. While some wines are designed to undergo secondary fermentation (like sparkling wines), this process is not suitable for still wines. Understanding secondary fermentation helps ensure that wines are handled correctly during production and storage, maintaining the quality and character intended by the winemaker.

So, as much as wine can be a source of joy, it’s important to recognise when a bottle isn’t quite right. By understanding these common faults, you can better navigate the occasional disappointments and appreciate the complexities of wine even more.

After all, the joy of wine lies not just in its perfection, but also in the journey of discovering what makes each bottle unique - faults and all.

And remember, when you do find that perfect glass, savour it, for it’s a reminder of just how extraordinary wine can be when everything goes right.

In the words of Galileo Galilei, the Florentine astronomer, physicist and engineer, "Wine is sunlight held together by water, a source of joy in every glass."  

Cheers!