Friedrich Bastian chugs to his island on a mini ferry.

Stefan Lergenmüller crosses over to his island with "Prussia's Gloria".

His former pilot boat also often transports tools for winegrowers.

28 larger Rhine islands belong to Rhineland-Palatinate and six more to Hesse.

But there are larger viticulture on an island in the river only on Bastian's island of Heyles'en Werth near Bacharach in Rhineland-Palatinate and on Lergenmüller's Mariannenaue near Eltville in Hesse.

Inselwein is a rarity throughout Germany.

The spokesman for the German Wine Institute (DWI) in Bodenheim near Mainz, Ernst Büscher, can only think of the wine island in the Main in the Franconian district of Kitzingen and the Lake Constance islands of Reichenau and Mainau with viticulture.

And now the North Sea islands of Sylt, Amrum and Föhr - thanks to climate change: "It's as if these islands had slipped 300 kilometers to the south."

Heyles'en Werth in the heart of the Upper Middle Rhine Valley World Heritage Site is 800 meters long, 150 meters wide and covered on the outside with a ring of poplars and willows.

They protect the wine, which grows on 1.7 mostly flood-free hectares, from the wind and the island from erosion.

The tree roots hold several meters of river sand that has been deposited on shale.

With the current low water level of the Rhine in the dry midsummer, the crown of trees seems to have moved upwards - entire shore zones around the island have fallen dry.

Islands have a microclimate

The Mariannenaue further up the Rhine is even larger, a good three kilometers long and 100 to 300 meters wide.

It belongs to the neighboring Schloss Reinhartshausen winery, which has been owned by the Lergenmüller family of winegrowers since 2013.

The island was once a limestone reef in the primeval sea.

Then the river washed up gravel and stones.

"Many people don't even know that there is viticulture in the Rhine," says Stefan Lergenmüller.

"Many people think at first that we're a small Hallig." Hidden behind rows of trees, the organic viticulture on the Mariannenaue extends over 24 hectares - many wineries have less vineyards.

Islands have a microclimate.

The Rhine stores heat, which it releases on cold and, above all, frosty nights – good for viticulture.

DWI spokesman Büscher says: "There is no drought damage either." Especially in the current low-rain midsummer, young vines on the mainland with still short roots are suffering from a lack of water in some locations.

On islands, however, viticulture can also be threatened by fungal attack in wet years, explains Büscher.

"It's a challenge." At the same time, island wine can be marketed very well as a rarity.

Island owner Bastian, a studied opera singer, grew up with Heyles'en Werth - an island as an adventure playground and place for children's birthday parties.

As early as 1815, when Napoleon lost his last battle, the island came to his family as a dowry.

In 1976 filmmaker Wim Wenders immortalized it in the film "Im Lauf der Zeit".

In 2021, Bastian leased Heyles'en Werth to another winemaker.

He wants to focus on his gastronomy around the "Grüner Baum" estate from 1421 on the market square in Bacharach and continue to organize small concerts, he says.

Wine tasting with and without the piano

The owner of the island, Lergenmüller, can also come up with centuries of history: According to him, the Weingut Schloss Reinhartshausen was founded in 1337.

This makes it one of the oldest wineries in Germany.

The offshore island was named after Princess Marianne of Orange-Nassau in 1902.

"Until 1986, the island belonged to the von Prussian family," says Lergenmüller.

Then other investors got involved first.

The Riesling grape variety grows on Bastians Eiland near Bacharach.

"I still sell 2018 island wine for 28 euros a bottle and the 2020 for 29.50 euros," says the restaurateur.

Before Heyles'en Werth was leased, he produced 5,000 to 6,000 bottles of island wine a year - with two employees who also helped him with other vines on the mainland.

Bastian does not reveal the turnover.

Lergenmüller speaks of around two million euros in annual sales with viticulture on the Mariannenaue.

Pinot Blanc, Sauvignon blanc and Chardonnay, for example, but also ancient grape varieties such as Adelfränkisch and Red Riesling grow here.

Five employees, Lergenmüller's wife and he himself take care of it.

At Weingut Schloss Reinhartshausen, according to their own statements, there are still around 60 hectares of vineyards on the mainland.

There are up to 20 employees in total.

Like Heyles'en Werth, the Mariannenaue is a natural paradise that has hardly been touched by humans: according to Lergenmüller, black kites, kingfishers and ospreys are out and about here.

And beavers.

"They're busy felling trees," adds the winemaker.

"Furthermore, deer and wild boar swim over to the island." Dragonflies and stag beetles cavort in the alluvial forest: "It's like a primeval forest," says Lergenmüller.

Some trees are up to 400 years old, "but sometimes also sick because of environmental influences".

For almost a decade, opera singer Bastian also transported a piano to Heyles'en Werth with his mini-ferry – for musical wine tastings.

Until the authorities banned him from transporting guests by boat for commercial purposes in 2017.

Lergenmüller still offers wine tastings on the Mariannenaue – without the piano.