Wines produce an abundance of different aromas, flavours, tastes and mouthfeel sensations due to the innumerable natural chemical compounds present from the grapes and other influences. Through the art and science of winemaking, these compounds will ideally contribute to a balanced and enjoyable wine-consumption experience.
However, that balance can be disturbed by excessive amounts of a certain compound or group of compounds that originate from grapes or from external sources. A classic example is cork taint, which results from undesirable compounds such as 2,4,6-trichloroanisole in wine corks. These are among a range of exceedingly potent aroma compounds that can impart their odour to an Olympic swimming pool with just one drop!
Another class of potent odorants, this time from grapes, is known as the methoxypyrazines. This includes 3-isobutyl-2-methoxypyrazine (IBMP), which contributes a “green” aroma and flavour reminiscent of green capsicum to grapes and wines. When present within certain ranges, IBMP adds desired “varietal” aroma and flavour to some grape varieties, typically cabernet sauvignon and sauvignon blanc. Being perceptible to the senses at only 10 ng/L (10 billionths of a gram per litre) in red wine, high concentrations of IBMP (>20 ng/L) may mask the pleasant fruity and floral bouquets of wines, leading to overpowering vegetative and...
