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Is that wine flawed… or just different?

In this episode of The Wine Lab, Andreea explores the difference between wine faults and flaws before turning to one of the most powerful forces in wine chemistry: oxidation.

What causes the bruised apple aroma in oxidized wine? What role does sulfur dioxide play in protection? Why did certain white Burgundies suffer from premature oxidation, known as “premox,” in the 1990s and early 2000s? And why are wines like Sherry and Madeira intentionally oxidative?

This episode blends wine science, history, and practical tasting guidance to help you recognize oxidation, understand aging, and taste with more confidence.

If you’ve ever wondered whether to send a bottle back — this episode is for you.

Acetaldehyde
A compound formed during oxidation. In small amounts it can add brightness to wine; in larger amounts it smells like bruised apple or oxidized cider. It is also a defining aroma in Sherry.

Aging
The natural evolution of wine over time. Aging includes many chemical changes, not only oxidation. Proper aging can enhance complexity, texture, and aroma development.

Aldehydic Aromas
Aromas associated with aldehydes like acetaldehyde. Common descriptors include bruised apple, green apple skin, nutty, or slightly sharp apple cider notes.

Balance
The harmonious relationship between acidity, alcohol, tannin, sweetness, fruit, and structure in wine. In the context of oxidation, balance refers to oxygen exposure remaining in proportion to the wine’s style.

Brett (Brettanomyces)
A yeast that can produce earthy, leathery, or barnyard aromas in wine. In small amounts, some consumers perceive it as complexity; in larger amounts, it is considered a fault.

Closure
The material used to seal a wine bottle, such as natural cork, synthetic cork, or screw cap. Closure choice affects how much oxygen enters the bottle over time.

Fault
A chemical or microbiological problem that makes a wine unacceptable to most consumers. Examples include cork taint, excessive volatile acidity, or strong sulfur defects.

Flaw
A minor deviation from ideal wine character that may or may not be perceived negatively, depending on the style and personal preference.

Micro-oxygenation
A winemaking technique where very small amounts of oxygen are added in a controlled manner, usually to red wines, to soften tannins and stabilize color.

Oxidation
A series of chemical reactions that occur when oxygen interacts with wine. It can cause browning, fading fruit, and aldehydic aromas if uncontrolled. In certain styles, it is intentional.

Premox (Premature Oxidation)
A phenomenon observed primarily in certain white Burgundies in the late 1990s and early 2000s, where wines oxidized much earlier than expected.

Reduction
A condition in wine caused by very low oxygen exposure. It can produce aromas like struck match, flint, or rotten egg.

Racking
The process of transferring wine from one vessel to another to separate it from sediment. This can introduce small amounts of oxygen.

SO₂ (Sulfur Dioxide)

A compound used in winemaking to protect against oxidation and microbial spoilage. It binds acetaldehyde and reacts with oxygen, helping preserve freshness.

Tannins
Natural compounds extracted from grape skins, seeds, and oak. They contribute to structure, mouthfeel, and aging potential.

Volatile Acid

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