Methoxypyrazines are powerful aroma compounds responsible for distinctive “green” characters in wine, including bell pepper, grass, herbal and earthy notes. Their concentration is largely determined in the vineyard, influenced by factors including vine vigour, canopy shading, light exposure and rootstock.

Associate Professor Dave Jeffery has contributed to several studies investigating these compounds. His research has explored how different rootstocks can influence methoxypyrazine concentrations in Cabernet Sauvignon grapes and stems, potentially through differences in vine vigour and canopy growth. His work has also demonstrated how the inclusion of stems during Shiraz fermentation can introduce otherwise uncharacteristic “green” flavours.

Jeffery’s research also highlights the complexity of how these compounds are perceived in finished wine. Other aroma compounds can mask methoxypyrazines, while methoxypyrazines themselves can alter the perception of smoky, fruity, floral and other aromas—even at concentrations below their sensory threshold.

The research provides valuable insight into how vineyard and winemaking decisions can be used to manage these potent compounds and ultimately influence wine style.