There is something that happens at each estate and in every vineyard. Every organ of the grapevine carries out a series of specific functions that, taken together, comprise a complete system which produces the fruit that eventually becomes wine, year after year, harvest after harvest.
The parts of the plant that arrive at the winery for vinification are as essential as those that stay behind in the vineyard and ensure the continued existence of the vine.
The parts that remain…
- Buds are small components along the cane located at each node in the leaf axil. They guarantee the renewal of the grapevine. Two buds develop at each node: the latent bud, which will sprout in the spring and contains the primordial inflorescences (future grapes); and the lateral or prompt bud, which produces lateral shoots, also known as summer laterals, during that season.
- Tendrils are a shared attribute of all climbing vines. They develop at the shoot tip and coil around objects, lignify, and provide support for the plant. Tendrils make it possible for vines to climb and “rise up” in search of sunlight.
- The leaves are the driving force and heart of the grapevine. They are the source of energy and life. The front and back – or surface and underside – of the leaf play different roles. The upper part (surface) is responsible for photosynthesis. The lower part (underside), normally covered in microscopic hairs, is responsible for gas exchange and transpiration.
Young leaves require a lot of energy to develop and consume all of the vine's sugar reserves. When they reach maturity, the remaining energy is directed towards other plant organs. The leaves gradually age, and in the fall, they wither, die, and fall to the earth.
…and the parts that are transformed
- Clusters or bunches of grapes are an iconic image. When we look closer, however, we can identify two different parts: the shoulders and the tip. This division is an important factor, because grapes do not ripen in a uniform fashion. The upper part of the cluster – the shoulders – contains a higher sap concentration, which means these grapes ripen earlier than those at the tip.
- The structural framework of the cluster consists of stems. They support the grapes and give the cluster its sculpted shape. Stems are usually removed at the winery through a process called destemming, because they contain an abundance of organic substances that can produce unpleasant, astringent sensations.
- Part of the grape skin (8–12%) is used during vinification. Here we're referring to the outer part of the grape skin which is covered in a grayish layer called the bloom. Wild yeasts present in the environment can be found in the bloom. The skin also contains various substances that produce characteristic varietal aromas, color, and astringency: polyphenols, flavonoids, and anthocyanins.
- The pulp is the soul of winemaking, the material essence, and represents the greatest percentage of the grape that is used in the vinification process (80–85%). The pulp is rich in water, mineral salts, sugar, aromatic precursors, malic and tartaric acid. It is not uniform in its makeup. This is why we differentiate between the central, or innermost, part that is rich in sugar and malic acid; the intermediate part which also contains sugar but in combination with tartaric acid; and a peripheral area with a highly complex composition: potassium salts, aromatic molecules, sugar, and acids.
The first pressing produces juice with a higher percentage of the compounds found in the inner parts of the grape, resulting in fresher, higher-acidity must than later press runs.
- The seeds or pips are rich in oils and tannins. Only a small percentage is used (2–6%) in red winemaking to add astringency and a certain rustic quality that recalls the wine's place of origin. The seeds have to be ripe in order to avoid green and excessively astringent flavors.
Every organ, every part, fulfills its particular function, and understanding one means understanding all of the others too. This is why viticulture is as important as the actual winemaking, because making wine begins in the vineyard..