The wide array of fruit, earthy, leathery, floral, herbal, mineral, and woodsy flavour present in wine are derived from aroma notes sensed by the olfactory bulb.
The term aroma may be further distinguished from bouquet which generally refers to the smells that arise from the chemical reactions of fermentation and aging of the wine.
An aroma refers to the smells unique to the grape variety and are most readily demonstrated in a varietal wine – such as lychees with Gewürztraminer or black currant with Cabernet Sauvignon.
As a wine ages and matures, changes and developments in aroma will continue to take place but at a slower and more gradual pace.
It is theorized that the Vitis vine developed these compounds as an evolutionary tool to aid in procreation by attracting insects to assist with pollination and birds and other animals to eat the berries and disperse the seeds.
The diverse spectrum of aromas associated with individual grape varieties is a reflection of the vine's adaptation to ecological conditions and competition among other plants.
[4] The majority of volatile compounds responsible for aroma combine with sugars in the wine to form odourless glycosides.
Scientists were able to use chromatograph – mass spectrometers to identify volatile aroma compounds in various grape varieties.
In 2004, a winery in South Africa was found to have added illegal flavouring to their Sauvignon blanc to enhance the aroma.
The precise yeast strain used during fermentation and temperature are two of the strongest indicators of what kind of esters will develop and helps explain partially why Chardonnay grown in the same vineyard but made by two different producers could have different aromatics.
A series of short, quick sniffs versus one long inhale will also maximize the likelihood of aromatics being detected.
The average human can be trained to distinguish thousands of smells but can usually only name a handful at a time when presented with many aromas.