Wine has many flavours and the esters are responsible for them by being substances that are formed by the combination of an organic acid and an alcohol. Therefore, they give pleasant smells and flavours to wine. Let’s learn a little more about esters.
What are the esters of wine and how do they form?
Such flavours and aromas are associated with fruity and delicate flavours, such as banana, raspberry and pineapple, for example, among many others, and they are detected in fruity wines. In total, more than 160 esters have been identified in wine, and many of them are produced in concentrations below our sensory threshold. When they are together, some esters can create a totally different aroma than the one they possess individually, while the presence of one can greatly affect the intensity of another.
It should be noted that a large majority of esters produced in wine are created during fermentation. Esters tend to be much less stable than these other aromas and reach their intensity at the end of the fermentation, when they dominate the character of a wine, but they degrade almost completely during the first year of the wine’s life and do not leave a long term mark.
Esters, in addition, tend to be more aromatic than alcohols, acids and aldehydes. During fermentation, yeasts produce fruity esters or short-chain esters, and heavier esters, which are the long-chain esters. The first ones are produced in low temperature fermentations and some examples are the Riesling and Chardonnay wines.
Formation of esters is quite complex because it depends on numerous reactions between multiple compounds. In general, esters are formed from reactions between alcohols (mainly superior alcohols) created by yeasts and components (usually fatty or organic acids) from grapes.
In addition to using aromatic yeasts, winemakers can also use carbonic maceration to achieve high levels of esters during fermentation. In addition to the yeast, the fermentation temperature is another important factor in the amount and type of esters produced, as well as the degree of retention in the wine.
For example, a winemaker who wants to create wines with high ester content will usually use an aromatic yeast, clear the must and then ferment the wine at a temperature as cold as the yeast can tolerate. It is not surprising that wine professionals discuss the impact of wild and commercial strains on fermentation.