Reductive aroma compounds: trait or fault

The standard

The threshold-based classification decides from the concentration relative to the perception threshold whether a reductive note counts as a trait or a fault. It also matters whether the note disappears under oxygen.

Criteria

• The concentration is measured against the perception threshold, not a total value
• Whether a note vanishes with air separates tension from damage
• Volatile and bound forms are kept apart, since only the volatile one smells
• The origin is kept separate from the effect

Distinction

Reductive aroma compounds ≠ reduction in wine: the compounds are the substances, reduction the condition. Reductive aroma compounds ≠ oxidation: opposite cause, equal risk of fault. The threshold-based classification tells them apart by behaviour under oxygen, not by smell.