The time of harvesting is determined by the sugar grading, the acidity and the health status of the grapes.
The amount of grapes harvested per hectare is dependent on grape variety, form of cultivation (for example organic cultivation), climate and weather conditions throughout the vegetation cycle, health condition of the grape material and, last but not least, on the quality aimed for as well as the targeted bottle price.
Harvest quantities can differ significantly. In certain areas that focus on mass production, harvests of 15,000 kg of grapes per hectare and more are possible. In Austria the law defines a limit of 9,000 kg for quality wine, respectively 10,800 kg per hectare in very good years.
In companies that strive for high quality wines and in vineyards that are terraced, an average of only 5,000 kg of grapes are harvested each year.
These vast differences in production quantities obviously have a huge impact on sales prices, margins and profits. The yield of a vineyard can be expressed in kg per hectare and in hectolitres. One hectolitre equals 100 litres. Per hectolitre, approximately 140 kg of grapes are needed.
Picking the grapes at a low temperature is an important objective during harvesting. Once grapes are picked, they should be delivered as cool as possible into the press house. Very warm temperatures lead to a risk of tannin input due to long maceration times and unwanted high activity on a microbiological level during maceration.
Harvest by hand as shown in the video allows the vintner to select the grapes carefully. Each cluster of grapes can be freed individually of dried or damaged berries as well as rot if present. The technique of grape enables a loose structure and prevents rot from developing at a very early stage. Grapes are transported to the tractor in buckets or wheelbarrows.
A sharp pair of scissors is of great help concerning the precise and adequate treatment of the grapes. The grapes are then filled into boxes that can take up to 400 kg.
Boxes are used as they can be easily emptied in the press house using a forklift. As a result, the mash does not have to be pumped and interference caused by trub during processing is prevented.
Apart from harvesting by hand, it is possible today to harvest by machine. Special harvesters offer the advantage of high working speed and fast harvesting of the grapes. Especially when temperatures are high, large areas can be harvested in the early morning hours in a short time.
However, to make this possible, it is necessary to have homogeneous grape material; sorting the grapes is of course possible but only to a very limited extent. By shaking the vine, the berries are shaken from the stem during harvesting by machine.
Shipping to the press house is normally done using trailers rather than using boxes as larger quantities must be transported in a short period of time.
The choosing of the harvesting technique is a fundamental decision of the winemaker and is influenced by the policy of the winery.