Common Off-Notes and Faults
Sulphur Compounds
**Rubber/burnt match:** Often from insufficient copper contact during distillation or certain sherry casks. Can dissipate with time and air. If persistent, it's a production characteristic rather than fault.
**Rotten egg/cabbage:** Hydrogen sulphide—more problematic. Usually indicates inadequate copper contact or contaminated casks. Rarely improves.
**Onion/garlic:** Sulphur compounds from fermentation stress or contamination. Generally considered a fault.
Cork Taint (TCA)
**Musty/wet cardboard:** Trichloroanisole contamination, usually from the cork. The whisky itself isn't spoiled, but the taint masks flavours.
**Detection:** If a whisky smells flat, damp, or cardboard-like, TCA is likely. Compare with a known good sample if possible.
**Prevention:** Quality cork selection, synthetic closures, or screwcaps eliminate this risk.
Oxidation
**Sherry-like/flat:** Extended exposure to oxygen in a near-empty bottle. Whisky oxidises faster than wine.
**Cardboard/stale:** Advanced oxidation. The whisky has lost its vitality.
**Prevention:** Consume within 1-2 years of opening. Transfer to smaller bottles to reduce air exposure.
Off-Notes vs Character
**Important distinction:** Some challenging aromas are intentional character, not faults.
- **Medicinal/phenolic:** Characteristic of Islay whisky, not a fault
- **Meaty/sulphury:** Can be desirable "old style" Speyside character (Mortlach, Ben Nevis)
- **Funky/yeasty:** Sometimes intentional fermentation character
Professional Response
When encountering off-notes: 1. Give the whisky time—some aromas dissipate 2. Add water—can reveal hidden character 3. Compare with another sample if available 4. Consider whether it's fault or character 5. Document for future reference