The Science of Wine (2/2)

Wine

19/12/2016

Ampelography

Ampelography is the science of studying, identifying and classifying different grape varieties. The discipline is also responsible for astonishing genetic discoveries that explain the origins of many varieties.

Physiology

Physiology studies the grapevine's growth cycle and root system (in botany, the root system refers to all of the roots of a given plant); how the plant absorbs water and draws organic matter and minerals from the soil; photosynthesis and how its products get distributed; secondary metabolites; berry growth and development... In short, this is the science that helps us understand and control what happens in a plant during its vegetative cycle and ripening period.

It is worth noting that climate change can have a significant physiological impact. For example, in Mediterranean countries, the vine has always been dormant during the winter months. If winters are too warm in the future, vines could be in an active state year round, which may lead to plants producing more than one harvest. This would have a negative impact on grape quality. We already see this happening in Thailand where vines are bearing fruit twice a year.

Agricultural engineering

All of this information is used by agricultural engineers to decide on the best design for any given vineyard. This means defining parameters like the planting scheme, vineyard orientation, the distance between plants and between rows, the height of support stakes, the drainage channels that remove excess rainwater, even the type of vine trellising (if any).

Chemistry and microbiology

Once we move into the winery, these sciences step into the spotlight.

Chemistry is crucial in analyzing grape compounds and controlling the entire vinification process.

The majority of aromatic compounds in wine come from the grape skins, where they begin as precursors that are then released by the action of the yeasts during fermentation.

Other compounds derive from the aging process: how the wine evolves while in contact with the oak barrel (oxidative process) or how the aromas interact during extended bottle aging (reductive process).

The phenolic compounds that give red wine its structure and astringency are also extracted while the must remains in contact with the grape skins during fermentation.

Microbiology studies microorganisms such as yeasts, which are essential to the alcoholic fermentation of wine, the process that turns sugar into alcohol.

It is important to work with selected yeasts, which ensure the appropriate organoleptic properties and bring fermentation to a satisfactory conclusion.

Lactic acid bacteria are integral to the process known as malolactic fermentation (MLF), which converts malic acid into lactic acid. This reduces the wine’s acidity, but adds complexity. Generally speaking, all red wines in Mediterranean regions undergo this process, but only certain high-acidity whites complete partial or complete MLF.

We could mention countless examples of how science influences winemaking. Every single decision that is made during the process has a direct impact on the quality of the finished wine.

Then tasters and wine lovers set their own human physiological and biochemical mechanisms in motion to sharpen their senses and identify aromas and flavors, which, as we have seen, make it to the glass thanks to an enormous amount of work and knowledge.

Here's to good wine and science!

Categorías: Wine