Author(s):
Gregory V. Jones* - Southern Oregon University
Hans Rainer Schultz - Geisenheim Research Institute
Abstract:
Harvest information for Riesling winegrapes from Schloss Johannisberg in the Rhine Valley, Germany from 1784-2007 has been compared to climate structure and trends. Harvest dates show a structure of later dates during the 1784 to 1895 period then a rapid change of over 25 days earlier since 1895, whereby harvesting commences in late September to early October today compared to late October in the earlier part of the record. This trend to earlier harvest dates is significantly related (R2=0.56) to minimum temperature warming during the growing season of 2.1°C since 1885. In addition, while winegrape yields and wine quality have fluctuated over the time period, a general trend to higher and more consistent yields and quality has been experienced. Over the last 20 years wines from Schloss Johannisberg and the Rhine Valley in general have not been declassified to lower quality, this trend is related to warmer and more consistent growing seasons that produce higher yields with higher quality wine.
