Vitis vinifera (common grape vine) is the only type of Vitis used for wine making in Italy. There are currently between 5000 and 10,000 varieties of Vitis vinifera grapes though only a few are of commercial significance for wine and table grape production, for example France has about 25 varieties while Italy more than 600.
It is a liana growing to 35 yards tall, with flaky bark. The leaves are alternate, palmately lobed, 5–20 cm long and broad. The fruit is aberry, known as a grape; in the wild species it is 6 mm diameter and ripens dark purple to blackish with a pale wax bloom; in cultivated plants it is usually much larger, up to 3 cm long, and can be green, red, or purple (black). The species typically occurs in humid forests and streamsides.
The wild grape is often classified as V. vinifera subsp. sylvestris (in some classifications considered Vitis sylvestris), with V. viniferasubsp. vinifera restricted to cultivated forms. Domesticated vines have hermaphrodite flowers, but subsp. sylvestris is dioecious (maleand female flowers on separate plants) and pollination is required for fruit to develop.
The Vitis has its own biological cycle. Once planted for the first years produces grapes poor of sugars and full of acidity not ideal for wine. It’s possible to produce wine with at least 5/7 years old plant which will offer than good grapes until the age of 50/70.
Its possible to talk of an annual cycle, which regards the production of the grape. Usually around february the plant start to “cry”, engendering its linfa. Between March and April the leaves are getting bigger and a premature stadium of grape (totally green like olives) starts to came out. June, July and August are the most important months where the grapes starts to mellow going from acidity to sugar.
The grape is the fruit coming out from the vitis and it’s composed by three different elements: the peel, the bulk and the seeds. The last ones are not used for wine making being full of bitter tannins and lignina (are good for oil instead).
The peel is really important. It’s responsible for the color, the aromas and the taste being rich of tannins, anthocyanins , leucoanthocyanins, aromatic substances (terpenes), cellulose and pruine. Pruine capture the yeasts in the air which are fundamental for the fermentation phase.
In the pulp we have water (80%), acids (tartaric, malic, citric), sugars (fructose and glucose), vitamins and nitrogenous substances.