Dr. Randolf Kauer, the charming, boyish, but apparently quite demanding professor of Organic Viticulture at the University in Geisenheim, has operated his tiny (3 ½ hectares) winery in Bacharach, the heart of the Mittelrhein, since 1982. Then there were few organic wineries, or for that matter, classes in Organic wine making, so Kauer was a kind of pioneer. The first imports to the US were in 2007 and now Winemonger has exclusive rights for the country.
His wines, all harvested in the steep, beautiful, slate vineyards overlooking the Rhein, are noted for their brilliant minerality and lively acid structure. Whereas Peter and Cecilia Jost emphasize their dazzling fruit, mostly from the Bacharacher Hahn, Randolf (with assistance from his younger daughter Anne) seeks an intense minerality. There is plenty of ripeness as well, but the balance is always towards a sleek, stony and refreshing balance, not exactly austere, but with the structure showing. The wines tend towards dryness, even the regular Kabinetts and Spätlesen. In some ways, these wines are more typical of the classic Mittelrhein style, hauntingly beautiful floral scents and a bracing, get-your-attention mouth feel and finish.
Randolf ferments entirely in old and neutral oak, using natural yeasts as much as possible (though he has no particular issue with occasionally adding cultured yeast). The cellar’s west wall is carved into the mountain and is pure slate and always wet. Thus it remains quite cool and assists in the slow development of the wines. Everything in both the vineyards and in the cellar, of course, is organic. The winery has been thus certified since the beginning.
The predominant variety at the Mittelrhein (about 95%) is riesling; there are virtually no reds, and the wines tend toward high acid, highly floral, and profoundly mineral-imbued.
The Mittelrhein is on the big river as it plows north after a twenty mile detour going west. The canyon is steep and the vineyards are on these steep slopes, virtually all of them slate. It's a blue slate, similar to that of the Mosel. Sometimes it looks almost like pure rock. It makes you wonder what on earth possessed the early monks to think of planting vines here (though, obviously, they grew on the slopes wild. But it is a beautiful area, with ruins of castles (some converted into fancy hotels) and walled towns and just wonderful scenery. The many tourist boats of all sizes attest to this.
For quite some time, the Mittelrhein was in decline. Good vintages only came about once in every 3-4 years. The work was extremely difficult on these steep slopes, and often you had to cross the river to get to them, which meant a ferry as there are no bridges between near Bonn in the north and all the way to Mainz in the south.
But good vintages have been consistent since the late '80s and the technology has improved. Even so, there are really only a couple areas, around Bacharach and around Boppard where wines of distinction are made. It is improving elsewhere, but that's still the general lay of the land.