If a wine seems “green”, “herbaceous”, or “vegetal”, aroma compounds called methoxypyrazines (MPs) could be responsible. MPs are particularly important due to their ubiquity in grapevines and their extremely low aroma thresholds. These low thresholds make MPs some of the most odor-active compounds found in wine. Occasionally, they can have a positive impact by providing varietal characters– classic examples are bell pepper in Cabernet Sauvignon and grassy/gooseberry in Sauvignon Blanc. However, higher concentrations can mask fruity aromas and damage wine quality.