Aromaticity

In organic chemistry, the term aromaticity is used to describe a cyclic (ring-shaped), planar (flat) molecule that exhibits unusual stability as compared to other geometric or connective arrangements of the same set of atoms. As a result of their stability, it is very difficult to cause aromatic molecules to break apart and to react with other substances. Organic compounds that are not aromatic are classified as aliphatic compounds—they might be cyclic, but only aromatic rings have especial stability (low reactivity).

Since one of the most commonly encountered aromatic systems of compounds in organic chemistry is based on derivatives of the prototypical aromatic compound benzene (an aromatic hydrocarbon common in petroleum and its distillates), the word “aromatic” is occasionally used to refer informally to benzene derivatives, and this is how it was first defined. Nevertheless, many non-benzene aromatic compounds exist. In living organisms, for example, the most common aromatic rings are the double-ringed bases in RNA and DNA. A functional group or other substituent that is aromatic is called an aryl group.

Aroma of wine

It is through the aromas of wine that wine is tasted. The human tongue is limited to the primary tastes perceived by taste receptors on the tongue-acidity, bitterness, saltiness, sweetness and savoriness. The wide array of fruit, earthy, floral, herbal, mineral and woodsy flavor perceived in wine are derived from aroma notes interpreted by the olfactory bulb. In wine tasting, wine is often smelled before being drunk in order to identify some components of the wine that may be present. Different terms are used to describe what is being smelled. The most basic term is aroma which generally refers to a "pleasant" smell as opposed to odor which refers to an unpleasant smell or possible wine fault. 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.

Aroma vs. bouquet

In professional wine tasting, there is generally a distinction made between "aromas" and a wine's "bouquet" while in casual wine tasting these two terms are used interchangeably. 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. These are smells that are commonly associated with a young wine. As a wine ages, chemical reactions among acids, sugars, alcohols and phenolic compounds create new smells that are known as a wine's bouquet. These can include honey in an aged Sauternes or truffles in a Pinot noir. The term bouquet can also be expanded to include the smells derived from fermentation and exposure to oak. In Burgundy, the aromas of wines are sub-divided into three categories-primary, secondary and tertiary aromas. Primary aromas are those specific to the grape variety itself. Secondary aromas are those derived from fermentation and oak aging. Tertiary aromas are those that develop through bottled aging.