How to spot spoiled wine

How does wine go bad?

You open a bottle of wine, pour yourself a glass and ask yourself: Does the wine still taste good or has it gone bad? Wine can indeed spoil – but not always at first glance. Some changes are completely normal, while others indicate a true wine fault.

In this article, you will learn how to recognize bad wine, what it means when a wine is corked, and why you usually don't have to worry about tartrates, sediment, or slight cloudiness.

Can wine go bad?

Yes, wine can go bad. How quickly this happens depends on factors such as storage, age, closure, and type of wine. While some wines can mature for years or even decades, others lose quality after just a few years.

Opened wine bottles, of course, don't stay fresh forever. As soon as oxygen comes into contact with the wine, its taste slowly begins to change.

How do you recognize bad wine?

The wine is corked

Perhaps you've heard before: "The wine is corked." Many people think of small pieces of cork in the glass – but the term actually means something completely different.

When a wine is corked, it has a so-called cork taint. This is usually caused by the chemical compound TCA (2,4,6-Trichloroanisole), which can form in natural cork.

Typical signs are:

• Smell of a damp cellar
• Wet cardboard
• Mustiness or mold
• Hardly any fruit aromas left

A corked wine is harmless to health, but usually tastes so unpleasant that you'd rather not drink it.

The wine is oxidized

Oxygen is one of the most common reasons why wine loses its taste. If a bottle has been open for too long or was not stored properly, the wine can oxidize.

You can recognize this by:

• White wine turning dark yellow or amber.
• Red wine developing a brownish or brick-red hue.
• The wine smelling of old apples, nuts, or sherry.
• It tastes flat and hardly fresh.

The wine smells of vinegar

If your wine smells distinctly of vinegar or even a little pungent, it's usually a sign that acetic acid bacteria have converted the alcohol into acetic acid.

Aromas reminiscent of nail polish remover can also occur. In this case, you should dispose of the bottle.

Sulfur smell – not always a wine fault

Sometimes wine smells of rotten eggs or slightly of burnt rubber. This seems off-putting at first, but it is not automatically a sign that the wine has spoiled.

Often, these smells disappear after a few minutes in the glass or after you have decanted the wine.

When do you not need to worry?

Not every visual change means that a wine is bad. Many peculiarities are actually a natural part of wine.

Tartrates

Small crystals at the bottom of the bottle or on the cork may look unusual, but they are completely harmless. This is tartrate, which forms naturally at cool temperatures. Tartrate is not a quality defect and has no effect on taste or health.

Sediment

Especially older red wines form a so-called sediment over time. These are deposited color and tannin compounds that collect at the bottom of the bottle. Sediment often even indicates that the wine was only gently processed.

Before pouring, you can simply decant the wine carefully.

Cloudiness

Especially natural wines or lightly filtered wines can look somewhat cloudy or contain fine suspended particles. This is also completely normal and no indication that the wine has gone bad.

Color changes

With increasing age, the color of many wines changes naturally.

• White wine turns golden yellow to amber.
• Red wine develops brick-red or slightly brownish tones over the years.

As long as the wine smells and tastes pleasant, you don't need to worry about it.

How long does opened wine last?

After opening, you should store wine as cool as possible and reseal it well.

As a rough guide:

• Sparkling wine: 1–2 days
• White wine and rosé: 2–4 days
• Full-bodied white wine: up to 5 days
• Red wine: 3–6 days
• Dessert wine: several weeks

The less air left in the bottle, the longer the wine will last.

Can you drink bad wine?

Most wine faults are not harmful to health, but merely impair taste and aroma.

However, if a wine smells or tastes strongly of vinegar, mold, or other unpleasant aromas, you should opt for a new glass instead.

How to keep your wine good for longer

With a few simple tips, you can maintain the quality of your wine for a long time:

• Store wine as cool as possible at about 10 to 15 °C.
• Avoid direct sunlight.
• Store bottles with natural cork preferably lying down.
• Protect wine from strong temperature fluctuations.
• Reseal opened bottles immediately and store them in the refrigerator.

Conclusion

Not every wine that looks different than expected is automatically bad. Tartrates, sediment, slight cloudiness, or minor color changes are often a natural part of a wine's development. Only when unpleasant odors such as damp cardboard, vinegar, or mold appear, or the wine tastes distinctly flat and oxidized, is it likely a wine fault.

Knowing these differences will allow you to enjoy your next bottle with peace of mind and quickly recognize when a wine is at its best and when it's time for a new bottle.