As a solution to the transport problem for the extremely valuable raw material wood, a wooden dam was built in 1798 west of Zwieslerwaldhaus in order to use the water from the Schmalzbach to transport the wood cut in the forests down the valley. The logs accumulated in front of the so-called Schmalzbach-Schwelle before the erected barrier was opened and the wood was “drifted” downhill with the force of the water masses on the straightened stream. The old construction was replaced in 1836 by an earth dam with a built-in “hermitage”. Since this locking device had to be operated by three forest workers, an accommodation hut was built for them. In 1870 the simple hut was expanded into an inn, the "Schwellhäusl". That year, violent storms caused extensive forest damage. Forest workers from the alpine countries were recruited to process the huge amounts of wood. At that time hundreds of these "guest workers" were working in the vast forests. The hut at the Schwellhäusl was an important base for the woodcutters. The Lettenmaier family has been managing the Trifterklause for more than 125 years, first as administrators and since 1980 as owners. The Schwellhäusl is a popular destination for hikers. Many paths lead into the wild and romantic surroundings of the Trifterklause. A trout pond, adventure playground, small animal zoo, the "jungle adventure trail" and a rock sundial enrich the environment today. The house has a wonderful beer garden, which even won a beauty award in 2002. The guests are pampered with hearty snacks, lunch, coffee and cake. For a hearty snack, you can drink "Bier vom Stoa" (steam beer) from the Royal Bavarian Cupbearer.