Our sense of smell is one of the least developed senses we possess. The olfactory mucosa is the organ responsible, measuring some 2 cm2 and located in the upper part of the nasal cavities, in a cavity away from the normal air passage. This subtle, fine, sensitive and well protected organ has two different access routes:
- Direct nasal passage. Occurring when the vapours from the wine glass are inhaled.
- The retronasal passage (or mouth aroma) occurring when the wine is ingested. During swallowing, a small amount of air is always expelled through the passage existing between the mouth and nose. In this way there is a mixture of gustatory and olfactory sensations.
The many different aromatic substances in wine (more than 600) are grouped into the following categories:
- Balsamic: resin, balsam, pastries ...
- Ascending: pine, eucalyptus, cedar, mint ...
- Animals: musk, mare's sweat, cat's urine ...
- Spices: laurel, pepper, nutmeg, clove ....
- Wood: tannin, oak from the barrels.
- Chemical: These are all negative (sulphurous anhydride, acetic acid, ethyl acetate ...)
- Empyreumatic: from the barrel toasting process, these are pleasant if in small quantities: smoke, fire, toasted bread, burnt caramel ...
- Floral aromas: carnation, rose, violet, broom aromas ...
- Fruit aromas: banana, strawberry, raspberry, coconut, blackberry ...
- Plant aromas: These can be pleasant (such as tobacco and undergrowth) but normally represent defects or a lack of maturity: green pepper, cucumber, rushes, wild garlic ...
A wine's aroma is a complex mixture that can have one predominant although never exclusive aroma.
The olfactory sensations vary with time, temperature and agitation, which makes wine tasting extraordinarily difficult.
The olfactory analysis is based on the following points:
- Frankness: non-interference of inappropriate aromas.
- Intensity: concentration and persistence.
- Fineness, elegance, complexity.
- Harmony.
The olfactory analysis comprises the following stages:
- The glass must be still. It is very important not to swirl the wine before this stage (everything in its own due time). Delicately smell the glass at a certain distance, gradually bringing your nose closer. In this way you will detect the most volatile, ethereal and fragile aromas, gaining an initial impression which can be far different from the one obtained once the wine is swirled.
- Swirl the wine in the glass. New aromas or new intensities will appear and which can then be analysed, identified and described. These compounds are less volatile and are only released after agitation.
Within a wine it is possible to distinguish:
- • Primary aromas. Aromas characteristic of each particular grape variety, such as the Muscat aroma. As such, they are often found on the grapes as precursors to those aromas whose characteristic notes only appear after vinification.
- Secondary aromas. Generated during alcoholic fermentation.
- Tertiary aromas. Primarily the esters developed during wine maturing and ageing (in the barrel and subsequently in the bottle).
Notes
- The term aroma is used to describe a young, undeveloped wine (whites that have not been aged, rosés, young reds).
- The term bouquet is reserved to describe the olfactory impressions of a mature wine that has been barrel aged.
- The carbonic gas frequently found in young wines (and also in sparkling wines) is a good vehicle for spreading aromas, and this type of wine therefore appears to be more aromatic. However, CO2 does not go well with the tannins found in red wine and it is therefore not recommended to use it with these wines (except for those wines produced by carbonic maceration with a low polyphenol content).