The distinctive aroma of Green Pepper (the 'Bellpepper' or Capsicum kind), comes from the group of aromas called 'pyrazines' which pack a punch; only a small amount of this aroma compound is needed for us to detect it. 

 

In wine, they are prominent in wines from the black grape Cabernet Sauvignon (green pepper) and the white grapes Sauvignon Blanc (asparagus, gooseberry, box leaf notes), especially when grown in a cooler climate. The pyrazine compounds are lost when grapes reach higher levels of ripeness in warmer climates. Other grapes related to Cabernet Sauvignon also develop pyrazines - the red grape Carmenere can have very distinctive 'snow pea' notes, and Cabernet Franc which can smell leafy. Bacchus, a cool climate grape develops distinctive green, herbaceous notes. 

 

Too many pyrazines may indicate underripe grapes and may be unpleasant if overpowering, especially as that may be accompanied by tart, mouth puckering levels of high acidity.

 

In some estates in Marlborough, New Zealand, where Sauvignon Blanc has found such a spiritual home, the vine rows are trained in such an orientation that only one side of the vine row gets full exposure to the intense New Zealand sun. This results in a variety of ripeness levels come harvest time, as some bunches have ripened fully, accumulating lots of sugar and tropical fruit notes, while the bunches on the other side are less ripe, with higher acidity and retaining plenty of pyrazine aroma compounds. This approach is one way to create balance in the final wine but also a broader spectrum of aroma compounds, and therefore more complexity.

 

If you smell Green Pepper in a red wine, along with high tannins, high acid, and a black fruit, blackcurrant (ribena, cassis) fruit character, it's a good sign you've got a Cabernet Sauvignon on your hands. 

 

If you smell herbaceous greenness or gooseberry, it’s a good chance you’ve got a Sauvignon Blanc or Bacchus on your hands!