Denomination (also known as wine grape) for those grapes from vines that are used to produce wine or spirits such as brandy(Armagnac, Cognac, Metaxa etc.) and even vodka (together around 85% worldwide). Other groups are table grapes (table grapes) and raisins intended for consumption. There are about 8,000 to 10,000 different grape varieties worldwide, whereby the morphology(leaf shape as well as size, texture and colour of the grapes or berries) is characteristic of the respective variety. The grapevine develops the grape during the annual vegetation cycle. As a rule, the grape harvest takes place at the best possible physiological ripeness. In the case of predicate wine types such as Spätlese, Beerenauslese, Trockenbeerenauslese or Eiswein, this takes place much later because a special grape condition is required for this. Especially in Austria and Germany, a certain sugar level of the grapes at harvest is an important criterion for the later wine quality level (see must weight).
Strictly speaking, the term "grape" is actually wrong; because a grape has only side stems without branches. The correct botanical name would be panicle. The size, the number of berries and the weight of a grape, as well as the number of grapes and the resulting yield per vine vary and depend on the grape variety, pruning, form of cultivation, weather conditions, wine quality and wine type (see the formula under yield). In a study lasting several years, researchers from the Weinsberg Viticulture Institute determined the average number of berries per grape of some classic grape varieties. The results: Silvaner 110, PinotNoir 115, Riesling 120, Kerner 140, Müller-Thurgau 160, Trollinger/SchiavaGrossa 155 and Lemberger/Blaufränkisch 190 berries. There was a considerable variation over different vintages. Lemberger, for example, was between 150 (2008) and 225 berries (2004), whereas Kerner was exactly the opposite, between 125 (2004) and 200 (2008) per grape.
During pruning, almost all grape varieties develop about 1.6 to 2.5 grapes per shoot, depending on their fertility. When bifocal cones are pruned, these values are slightly, but sometimes significantly lower, depending on the variety. For example, Gewürztraminer with approx. 0.5 to 0.8 grapes per shoot would have extremely low fertility. In the Dornfelder, approx. 1 to 1.3 grapes/shoot can be expected. Riesling still shows quite high fertility even with this pruning system with about 1.5 to 2 grapes per shoot. The average weight of a grape is 180 to 200 g (Riesling 100 to 200 g, Pinot Noir 150 to 230 g, Blaufränkisch 180 to 280 g). A vine with 8 to 12 grapes gives a total weight of 1.5 to 2.5 kg. This results in 1.5 to 2 bottles of wine with the standard volume of 0.75 l.
The grape must obtained by pressing (pressing) forms the basis for the wines. The residue is called marc, the sediment after fermentation is called tank bottoms. Both are used to produce high-quality brandies by distillation. The grape berry sits on a short stalk, which is located on the stem framework (comb or centaury, bot. pedunculus). At the opposite end there is a dead tissue on the surface, which represents the rest of the stylus and the stigma (female organ) of the former flower bud. The number of berries per bunch depends, among other things, on the course of the vegetation cycle and the grape variety and can range from several dozen to 600 or more berries. Compact, dense-berried grapes are susceptible to fungal diseases and grape rot, so a certain amount of loose berries is advantageous.
From each individual blossom of a peach, a grapevine is formed, provided that fertilization has taken place. Under the skin of the grape is the slugs (light-coloured flesh) which connect to the stalk. Below this are the darker fruit flesh (pericarp and mesocarp) and the fruit juice (grape must). With the exception of the red-fleshed Teinturier varieties, the flesh is always light to grey, regardless of the colour of the skin (bellows). The berries contain the main components(water, acids, sugar etc.) or other ingredients of the future wine and give it its character (see total extract). In the centre of the berry is the core chamber with mostly two to three, in rare cases up to five or maximum six seeds. A different grape variety can potentially develop from each of the seeds (see flower and flower bud).
So-called seedless berries, which are desirable in table grapes, also contain seeds, but smaller ones in smaller numbers, as well as a soft consistency so that they are hardly noticeable when eaten. The seeds are not so important for vinification, they also contain tannin. In white wine they are usually separated from the grape must with all other solid parts during pressing. Particularly in red wine, the mash fermentation leads to longer contact between must and mash and thus also with the pips. The seeds are also used by individual producers for the extraction of grape oil.
There is a direct correlation between berry size and wine quality, which is particularly beneficial for red wines when they are made from small-berry grapes. The berry skin (pods or bellows = exocarp) contains the important taste-determining substances anthocyanins (colouring agents) and phenols such as tannins. With smaller berries, these substances make up a higher proportion due to the resulting better ratio of surface to volume. Potentially good wine press grapes actually lift much smaller berries compared to table grapes (which, when used as wine press grapes, produce a rather simple wine). On average, a high-quality Cépages nobles berry weighs one to two grams, and up to ten grams for smaller varieties. In the vineyard, efforts are also made to achieve higher quality by measures such as deliberately inducing water stress and thus smaller berries. An important quaslity criterion is also a balanced proportion of sugar and (especially for white wine) acids.
All aids, work and measures in the vineyard during the vegetation cycle can be found under vineyard care. Complete lists of the numerous cellar techniques, as well as a list of the types of wine, sparkling wine and distillate regulated by wine law can be found under vinification. Comprehensive wine law information can be found under the keyword wine law.
Grape and flower bud: Common free, Link
Grape varieties: Ursula Brühl, Doris Schneider, Julius Kühn Institute (JKI)
Grape upstairs: From fr:Yelkrokoyade - author, CC BY-SA 3.0, Link
Grapevine downstairs: By Mariana Ruiz Villarreal (LadyofHats), Public domain, Link
edited by Norbert Tischelmayer, March 2019