Gunderloch is a thriving estate of approximately twenty-five hectares of vines in some of the top vineyards of the "Roter Hang" ("red slope") area in the Rheinhessen appellation. In Nackenheim they own the dominant portion of the grand cru Rothenberg (sixty-five percent of the estate’s holdings) which is planted completely to Riesling. Their GG from here is the flagship of the estate; their noble sweets from the site are legendary. The other part of their production comes from five kilometers down the road in Nierstein, where they work steep parcels of vineyards whose names resound to the ears of German wine lovers: Niersteiner Pettenthal and Niersteiner Hipping, which both provide GG wines for them. The average yield is held to forty-five hectoliters per hectare, among the lowest in Germany, resulting in wines of high extraction and great quality. Minimum ripeness for the various quality levels is significantly above the requirements of the German wine law. The wines are never de-acidified and in high acid vintages bottling is often delayed to allow the wines to harmonize and soften. The cellar work is accomplished with a minimum amount of handling and has traditionally been reductive in style—although that is now changing as Johannes pursues his explorations in winemaking. After much experimentation and rethinking of received wisdoms, Johannes is making signifcant changes at Gunderloch.