A term (also known as ‘wine grapes’) used to describe grapes from vines that are used for the production of wine or spirits such as brandy (Armagnac, Cognac, Metaxa, etc.) and even vodka (together accounting for around 85 per cent of global production). Other groups include table grapes (grapes for eating) and raisins. There are around 8,000 to 10,000 different grape varieties worldwide, with the morphology – such as leaf shape, bunch shape (shouldered wedge shape or unshouldered cylindrical shape), the structure of the bunch, and the texture and colour of the berries are characteristic features of each variety. The structure of the bunch, together with the arrangement and size of the berries, also results in bunches ranging from loose to (as shown in the diagram on the left) tightly packed.

1 = main stalk (pedunculus), 2 = lateral branch, 3 = Berry stalk (pedicel), 4 = berry, 5 = main axis (rachis), 6 = branching point, 7 = Berry stalk, 8 = lignification of the raceme framework during ripening

Growth cycle

The vine develops the grapes during its annual growth cycle. As a rule, the grapes are harvested when they have reached the optimum physiological ripeness, which is a prerequisite for high quality. For premium wine categories such as Spätlese, Beerenauslese, Trockenbeerenauslese or Eiswein, this takes place much later, as a specific condition of the grapes is required. In Austria and Germany in particular, a specific sugar content in the grapes at the time of harvest is an important criterion for the subsequent wine quality classification (see ‘must weight’ for more on this).

Grape = raceme

Strictly speaking, the term ‘grape’ is actually incorrect, as a ‘grape’ has only lateral stems without branching. The correct botanical term is ‘raceme’. Grapes are classified as non-climacteric fruits, which means that they do not continue to ripen after harvest. The size, number of berries and weight of a bunch of grapes, as well as the number of bunches and, consequently, the yield per vine, vary and depend on the grape variety, pruning, vine training, weather conditions, wine quality and wine type.

Amount of grapes required for a bottle of wine

The quantity of grapes required to produce a 0.75-litre bottle of wine depends on several factors. These are primarily the grape variety and the winemaking methods. The ranges of variation in the figures given in the table are relatively wide; the quantities stated are averages. A multi-year study by the Weinsberg Viticulture Institute determined the number of berries per bunch for a number of classic grape varieties.

• For quality wine grape varieties, a single berry weighs only 1 to 2 grams (see also below)
• As a rule, 1 kg of grapes yields between 0.6 and 0.8 litres of must 
• During the fermentation process and other methods (e.g. clarification, filtration), approximately 10 to 20 per cent of the volume is lost
• A 0.75-litre bottle of wine requires around 1.2 to 1.5 kg of grapes