Where do the aromas in wine come from?

A glass of wine can offer an immense olfactory landscape that our brain interprets using our emotions and memories. If you’ve ever tasted a berry from a wine grape variety like Chardonnay or Gamay, you’ll find that the flavor is vastly different from what you taste in a glass of wine (except for Muscat and unripe Cabernet Franc berries). For example, wine made from Gamay can have a range of aromas, such as gooseberry, banana, strawberry, and others, depending on the wine, the region, and the winemaker.

All the aromas and flavors you taste and smell in a wine come from grape berries (and other vegetal parts of the vine). If Chardonnay has apple and Chenin has peach aromas, it’s because these grape varieties produce the same aromatic molecules as apples or peaches. For example, Chardonnay often has fresh aromas of apples and citrus, sometimes with a touch of peach and butter, and sometimes with floral scents. How can it be possible?

The creation of wine aromas can be broken down into three groups: primary, from the fruit; secondary, from fermentation; and tertiary, from the aging process. Most of these aromas are present in some form in the grapes (and sometimes in bacteria or in the wood used to age the wine). The Chardonnay’s ability to express apple aromas is due to the presence of the molecule responsible for this fragrance, either as a fully expressed aromatic molecule or as a precursor.

If you taste a fresh berry from a wine grape variety, you’ll only taste grapes because most aromatic molecules are in the form of precursors. The expression of an aroma depends on the creation of these precursors and the transformation of these precursors into aromatic molecules. This takes place in the vineyard and depends on factors such as the soil, the environment, the climate, the grape variety, and the winegrower’s techniques. The grape variety is a major determining factor in the creation of aromas. Some varieties are known for producing rose, lychee, and exotic fruit aromas, while others have a different range of aromas. For example, a wine with mineral aromas with smells of stone and flint is the result of the vine’s behavior in a certain type of soil. The plant uses minerals from the soil to create precursors that produce these characteristic aromas. The roots don’t extract minerals alone; they need the help of mycelium, a microscopic mushroom that digests minerals and oligo-elements and returns them to the roots. These elements contribute to the creation of aroma precursors and connect the soil, the terroir, and the wine. Treating a vineyard with pesticides and other aggressive treatments risks reducing the number of precursors, while organic and low-intervention methods preserve the life in the soil.

The climate, sun exposure, and water stress also play a role in creating these precursors.

These precursors are revealed through fermentation. Yeast breaks down precursors to produce aromas. If there are low levels of precursors, the aromas will be bland. If there are high levels of precursors but the yeast can’t break them down, the wine will also have poor flavor. Yeast is an important factor in winemaking as it converts sugar into alcohol, which reveals the aromas present in the juice in the form of precursors. Some yeasts are better than others. For example, the industrial yeast used in conventional Beaujolais Nouveau can produce unpleasant banana and English candy flavors that mask the fruity aromas Indigenous yeast is not the same, they share the same soil and the same climate and usually can reveal most, if not all the aromas of the wine.

Aromas are part of the emotion a wine can give you. Wine is a delicate product, the less intervention you have the better expression you get. It is not a golden rule, you can enjoy a conventional wine, full of taste and hate a natural wine with shitty flavor. But most of the time, wine is the computation of a winemaker and winemaker with the land, the climate, and the soil. It is an artisan process, a craft product. If it takes care of the land, the plant, and the fruits, the chance you will get a good product.