Phenol concentrations are varietal specific and can be manipulated by both viticultural and enological methods. This can completely change the flavor and qualities of a wine. In addition, these molecules play an important role in wine and health.
Flavanoids and Non-Flavanoids
Chemically, phenols are compounds containing a cyclic benzene ring and one or more hydroxyl groups. If that sounded like a different language, don’t worry, its not important. But what is important is their role in wine. Phenols are subdivided into two major groups; flavanoids and non-flavanoids.
The Role of Phenolics in Wine
Any bottle of wine contains over 1000 distinct chemicals. This is even more drastic considering that 95% of the total volume is occupied by water and alcohol. So it is within 5% of the volume that the differences between wines are seen.
Grapes and the subsequent wine they produce contain hundreds if not thousands of phenolic molecules. The most noticeable characteristic of these compounds are astringency and bitterness, particularly in red wines. They tend to balance sweetness, as seen in this dynamic:
Sweet Taste (sugars + alcohols) <= => Acid Taste (acids) + *Bitter Taste (phenols)
Phenols do not only affect taste. They also give red wine color, and act as a preservative during the aging process. Most phenols exist in the form of tannins. These molecules help to preserve wine by their ability to absorb oxygen. When a wine turns brown due to oxidation, it is the phenol reaction with oxygen that causes this color change.
The weight of a wine on the palate is largely a result of the interaction of phenols with other compounds in a wine. Because these interactions change through aging, the perceptible astringency can be very different in a young red when compared with an aged one.
What exactly are Phenols?
Phenols are a class of compounds containing a phenyl ring and varying substituents. This class of compounds is found in many organisms; from animals and plants to small microbes. They are used by animals and microbes as defense mechanisms, and by plants as protection by stopping biologically active growth inhibitors. So what does this have to do with the wine in your glass?
Since phenols are developed as a defense mechanism for plants, the more stressed the vines are, the more phenols the plants will produce. This can be seen when you compare a jug wine from the central valley and premium quality Mt Veeder Cab.
Most of the phenols in wine are primarily derived from grape skins, stems and seeds. Some also form during the fermentation and aging process, but these are small compared to the amount naturally present.Related Articles
- Acidity in Wine
- Alcohol in Wine
- Chemical Components of Wine
- Chemical Nature of Varietal Aromas
- Sugar in Wine
- Wine Acids