What Gives The Wine Its Peppery Aroma?

A good wine's quality is the result of a combination between a sandy soil and the hot and dry summer, besides the grape variety. The strain of yeast used in the fermentation process can also give particular features of a top quality wine, like smell, color and flavor.

Now, Australian chemists have come with the molecule that gives the red wine its peppery aroma, and which could allow wine producers to manipulate the bouquet of their productions. Black pepper aroma and flavor are crucial for characterizing some red wines, like those made with Shiraz grapes, but there was no method to determine during the fermentation process if the peppery aromas had been developed, as the chemical(s) responsible for this was not known.

Five years of research were necessary for a team at the Australian Wine Research Institute in Adelaide to search for the perfect fragrance and the Australian researchers discovered that just one chemical was determining the spicy smell. The grapes used for the investigation came from Victoria and South Australia. "Known as alpha-ylangene, that compound is so pungent that a single drop is enough to make an entire Olympic-size swimming pool smell peppery," said institute chemist Mango Parker.

"The finding could have major implications for the multi-billion dollar Australian wine industry, as Shiraz constitutes one-fifth of its output and is by far the most popular red variety. If you can measure something, you can understand its behavior and how to control it," said Parker.

"Winemakers might one day alter the pepper aroma in red wine the same way they now alter its characteristics with different yeast varieties or oak barrel fermentation. While scientific instruments such as a mass spectrometer were used to track down the aroma compound, which has a concentration of one part per billion, old-fashioned methods were the most effective. At the end of the day, a lot of people did a lot of sniffing throughout the research. Our noses were our most sensible and reliable detectors.", she explained.