Osterberg is a named vineyard of the Alsace Grand Cru appellation in the commune of Ribeauville in Alsace, north-eastern France. It is one of three Grand Cru sites which sit above the northern side of Ribeauville, each occupying a distinct section of the hillside. Kirchberg is the highest and most westerly of the three, sitting just above the Geisberg site which sweeps from south to east around the apex of the hill. Osterberg occupies the eastern section, as its name ('East Hill') implies. White wine is produced from four grape varieties; 46 percent of vines are from Riesling, with Gewurztraminer and Pinot Gris forming the bulk of the remainder, and a few rows of Muscat completing the list.
(© CIVA)
Osterberg is by far the largest of the trio, covering nearly 25 hectares (62 acres). It is also the most gentle, with its slopes rising steadily from the eastern end of modern Ribeauville (the old town is located to the west). The lowest Osterberg vines are located at an altitude of 250 meters (820ft) and climb to roughly 350m (1150ft). The site's perfect south and south-easterly aspect exposes the vines to gentle morning sunshine throughout the growing season, resulting in complex, delicately flavored wines. There is a perceptible difference between a Riesling from Osterberg's terroir and one from the hotter, more-exposed slopes of Kirchberg, just a few hundred meters away over the hillside.
The bedrock beneath Osterberg is composed of stratified marlstone and limestone formed in the Triassic and Jurassic periods respectively. This is covered by a thin layer of relatively free-draining soil made up of loose sandstone. There is also a significant clay component here, with good water-retention properties that often prove valuable in Alsace's characteristically dry climate.
The climate throughout Alsace is of continental type with particularly low rainfall – a result of the rain shadow cast by the Vosges. The mountains also provide protection from the prevailing westerly winds, making the Alsatian summer one of the driest and warmest in the northern half of France. At the other end of the temperature scale, the winters here are cold; it is not uncommon to see Alsace vineyards lined with snow.
