What is the grape harvest? The delicate time in which a year’s work is completed
It is the moment in which the grapes are harvested: this operation can be carried out manually, usually in inaccessible areas (Etna, Cinque Terre, Valtellina, the Amalfi Coast and Valle d’Aosta), where it is known as heroic viticulture. Special machines can then be used, which allow production times and costs to be reduced.
Due to the high daytime temperatures, for example in Sicily, the grapes are harvested at night using lamps for light.
What factors influence the grape harvest?
Generally, the harvesting period coincides with the end of summer and the beginning of autumn. In reality, the final result is influenced by numerous factors:
- Aromatic, phenolic and technological ripening: by aromaticripening, we mean the accumulation of aromatic substances in the grape skin, known as varietal aromas. Phenolicripening instead refers to the optimal level of maturation of the polyphenols, which should be more concentrated in the peel and seeds. The ratio between the sugars – present in the pulp – and acids indicates the degree of technological ripeness. This is usually achieved between the second half of August and the end of October in the Northern Hemisphere, depending on the climate, seasonal trends and grape variety.
- Geographical area: In the Southern Hemisphere, the seasons are reversed: in New Zealand, for example, the grapes are harvested in the months of March and April!
- Type of wine to be produced: To obtain sparkling wines,
the grapes must have a good level of acidity (especially malic and tartaric
acid) and elegant aromas. They are therefore harvested earlier than others,
given that acidity decreases with ripening and sugars subsequently increase.
For red-seeded grapes, you are required to wait until the tannins – responsible for the astringent and mouth-puckering sensation in the wine – are no longer unripe and a greater structure is often needed, meaning that the grapes must be perfectly ripe in order to concentrate the sugars that will be converted into alcohol.
What is the late harvest and how does it affect the wine?
In order to obtain sweet, smooth and structured wines, the grapes are left to mature for longer on the plant and, in some territories with particular geo-climatic characteristics, can be attacked by Botrytis cinerea, better known as ‘noble rot’, which will give the wine a greater olfactory-gustatory complexity. This process is called the late harvest. Typical examples are the Sauternes wines of France and the Tokaj wines of Hungary. Alternatively, Ice Wines are wines that are obtained from grapes harvested after Christmas, when the bunches have frozen, so as to concentrate the sugars, acids and salts. Aromatic grape varieties, such as Riesling and Gewürztraminer, are preferred and produced with excellent results in Canada, Germany and Austria.
The secret to a good grape harvest: selecting the bunches
Another element not to be underestimated is the selection of the best bunches, so as to avoid harvesting unhealthy grapes. This can be done at the time of harvest, if done manually, or on sorting tables where the boxes used for transport from the vineyard to the cellar are emptied. Some companies have sophisticated machines that do this job for them to a very high standard: a process required for the production of premium-quality wines.
The boxes used for collection during the grape harvest must have a maximum capacity of 20 kg to avoid – to the greatest extent possible – crushing the grapes, releasing the juices and possibly initiating undesirable chemical processes.