The wonder of Botrytis

Ripe grapes taste sweet. But how is this sweetness revealed in the wine? When the grapes hang from the vines as long as possible in the Fall, the natural sugar in the grapes becomes concentrated.

A picture shows Botrytis
© AWMB

For the Spätlese- and Ausleselevel wines, this concentration takes place mainly without any noticeable changes to the grapes, while for the higher Prädikatswein level wines, a wondrous change in the grapes can be observed. When ripe white wine grapes are infected during favourable conditions by the Botrytis cinerea fungus, the so-called “noble rot” develops. The growth of the fungus is nurtured by humid air while, at the same time, the water in the grapes evaporates. This occurs especially during the Fall, when early morning fogs are followed by warm, dry afternoons. These conditions are ideal in the Pannonian region around the Neusiedlersee, for example, because of the balancing effect provided by the vast amount of water in the lake. It begins with the break-out of Botrytis in the healthy, ripe grapes. Gradually, more and more berries become infected. The fungus penetrates the grape skins and feeds on the liquid while water evaporates through the holes; eventually the grapes shrink to a raisinlike state. The remaining contents, such as sugar, acidity and extract, become extremely concentrated.

The harvest requires the utmost in attention and care, as grape selection in the vineyards must be carried out in more than one step. This is necessary in order to acquire the optimal grapes for the Beerenauslese, Ausbruch or Trockenbeerenauslese quality categories. The higher the must gradation – along with this, the natural sugar content in the must – the more difficult it is for the yeasts to convert sugar into alcohol. Therefore, the fermentation can last for several months. These intensive efforts pay off nicely, though. The wines exude unique aromas and flavours, thanks to the wonder of Botrytis. Its magic produces expressions of honey and dried fruits, as well as exotic and even Christmas time fragrances and tastes.

The speciality Ausbruch is at home in the historical free town of Rust on the western shore of the Neusiedlersee. This wine is steeped in tradition: its first-known documentation goes back to the mid-16th century. In 1681, the Reichstag in Ödenburg declared on December 3rd that the market town of Rust
would be raised to the status of a royal free town. And for that privilege, the citizens of Rust had to pay Emperor Leopold I (1640-1705) "real and liquid gold" - specifically, the enormous sum of 60,000 Guilders as well as the entire vintage – some 30,000 litres - of Ruster Ausbruch wine. These traditional sweet wines eventually made their way from Rust to the imperial and royal courts of Europe – even all the way to St. Petersburg. Today, the wines are undergoing a new kind of renaissance.