The carbonated sour-well water comes from about 15-20 meters depth. Three to four liters of water per minute flow at a temperature of ten to twelve degrees from the depth. This water was already used by the Celts and Romans to quench their thirst. The Romans used the acidic water to stimulate circulation and metabolism and for wound treatment. Julius Caesar is said to have already drunk from this source. Because of the high iron content, the platform around the source is rust-colored. The hiking trails Römersteig, the ninth Moselsteig and the Schiffswanderweg intersect here.