What are some common wine faults caused by improper winemaking?

The correct answer highlights common wine faults directly linked to improper winemaking practices. Cork taint is a result of a compound called TCA (2,4,6-trichloroanisole), which can be introduced through contaminated corks, leading to undesirable musty aromas and flavors. Oxidation occurs when wine is exposed to too much oxygen during production or aging, causing a loss of freshness and the development of undesirable browning flavors. Volatile acidity, primarily caused by acetic acid bacteria, can result in high levels of vinegar-like aromas and flavors, impairing the wine's quality.

These faults stem from inadequate handling, storage, and bottling processes, highlighting the importance of sanitation, controlled exposure to oxygen, and appropriate cork quality in wine production.

The other options mention conditions that may not necessarily be classified as faults. Excessive sweetness, for example, can be a stylistic choice in certain wine types rather than a fault. Green flavors might arise from unripe grapes, while low alcohol and cloudy appearance can occur due to various vinification choices but are not definitive indicators of faults. Fermentation stalls and wild yeast can also be seen as issues but aren’t classified as faults in the same way as cork taint, oxidation