WHAT IS AN ASZÚ GRAPE?
Two phenomena form the aszú grape: the fungus Botrytis cinerea and shrivelling on the vine stock. The balance between these two determines the aszú berry and thus the character of the vintage. The nature and the quantity of the aszú grapes picked vary every year.
Botrytis (Noble rot)
The fungus Botrytis cinerea settles on the ripe or very ripe grape. It only appears when the necessary amount of humidity is present – coming either from damp autumn weather or vapour and fog rising from the Tisza and Bodrog rivers and their oxbow lakes. First the fungus enters the grape weaving its threads through the flesh. In some vintages the fungus develops on the skin. In response to the Botrytis, the grape creates aroma precursors that will be changed later and bring the specific “Botrytis” notes of citrus. It is important that the Botrytis settles on ripe grapes, otherwise it causes grey or green rot.
As a result of Botrytis and full ripeness and Botrytis, the skin of the grape becomes thinner and develops holes, so the water evaporates more easily. As the grape loses water, it shrivels and becomes an aszú grape in which the sugars, acids and flavour components are increasingly concentrated. Warm autumn winds and sunshine also aid the natural shrivelling process.
Continue to learn more information about:
- The Magic of Botrytis (video)