Wine glass shapes tastebud

Wine connoisseurs have always claimed that the shape of the glass affects how easily volatile aromatic compounds can escape and consequently the impact on our senses- but does the glass shape also affect the wine's chemistry? New research suggests that this could be the case, reports the New Scientist​ this week.

Kari Russell of the University of Tennessee, US measured the concentration of phenolic compounds in a Merlot as it sat in three different glasses: a flute glass, a Martini glass and a wide Bordeaux glass.

Phenols are ring-shaped compounds containing hydroxyl groups, and as antioxidants are thought to be responsible for some of the health benefits of moderate red wine consumption.

After pouring the wine, Russell found that the concentration of a phenolic compound called gallic acid increased, most likely because the action of pouring triggered reactions that converted gallic tannins in the wine into gallic acid.

But between 10 and 20 minutes later, the concentration of gallic acid in the flute and Martini glasses remained high, while the concentration in the Bordeaux glass fell.

According to the New Scientist report Russell believes that this is because a higher surface area of the wine is exposed to air in a Bordeaux glass. Oxygen drives the formation of compounds called catechin-gallate esters from the gallic acid. When esters pass your lips, they precipitate the proteins in your saliva, making the wine taste dry.

Although Russell saw a similar chemical development for other phenolic compounds, the shape of the glass did not make such a difference.

After decanting wine into an inelegant lab beaker to prevent psychological bias, she asked a panel, mostly of students, to taste wine that had sat in different glasses.

The majority did not notice any difference. But one panellist - an older professor - did seem to be able to tell. "I think with training the glass might make a difference,"​ said Russell.