Eisstollen Dornburg

Ewiges Eis - Eternal Ice

Useful Information

Location:	65599 Dornburg. From Dornburg L3278 to Wilsenroth, after 900 m turn right to parking lot/trailhead. 300 m/5 minutes walk. (50.519723, 8.024994)
Open:	no restrictions. [2023]
Fee:	free. [2023]
Classification:	Ice Cellars
Light:	bring torch
Dimension:
Guided tours:	self guided
Photography:	allowed
Accessibility:	no
Bibliography:
Address:	Gemeinde Dornburg, Rathaus Frickhofen, Egenolfstraße 26, 65599 Dornburg, Tel: +49-6436 9131-0. E-mail:
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then. Please check rates and details directly with the companies in question if you need more recent info.

History

1839	Workers removing stones for road construction in the boulder field on the southern slope of the Dornburg discover icing about half a meter below the loose blocks of rock.
1869	J. Troost from Wiesbaden has a brewery built on the southeast slope of the Dornburg.
1886	Brewery on the Dornburg burns down.
1927	Naturschutzgebiet Dornburg (Dornburg nature reserve) designated.

Description

The Eisstollen Dornburg (Dornburg Ice Tunnel) is an artificial gallery that was created to take advantage of a natural phenomenon, the only permafrost in Hesse, to cool beer. A very laudable approach, but unfortunately it ended with a fire and the destruction of the brewery. Today the two tunnels are gated with iron bar doors, so they can only be visited from the outside. However, they are not that interesting either. What is interesting is the temperature anomaly at their entrances; even in midsummer it is only 7 to 10 °C here.

But let's start at the beginning: the Dornburg is a basaltic hill between Frickhofen and Wilsenroth. On its southern slope there is a scree of basalt, which itself is not overgrown, but surrounded by forest. The crevices in the scree allow air to flow through. This creates an air convection between the base of the dump and the top of the dump. In summer, cold air flows out of the mountain at the bottom of the slope because it is heavier. As a result, warm air is drawn in at the upper end, which then also cools between the cold rocks. In winter, this effect is reversed and warm air flows out of the mountain at higher points. This air, which is at least warmer than 0 °C, also causes these places to remain free of snow. Cold air is sucked in at the bottom and warms up on the rocks, but cools them down in the process.

Such effects are not unknown, but many details have to come together, and so they are quite rare worldwide, this is the only such place in Hesse. Particularly interesting is not only the fact that in summer cold air flows out at the foot of the scree. Due to the equilibrium prevailing here, the basalt scree itself is colder than 0 °C all year round in a larger area. This is called permafrost, so this is the only piece of permafrost preserved from the last Ice Age. Ice is found between the loose rock from about 50 cm to a depth of 2 meters. Below that, the ground is frozen to a depth of 5 to 8 m. At a depth of 8 m the ice stops. Three springs at the foot of the Dornburg have a temperature between 5° and 6° C all year round. The Dornburg ice tunnels are part of the National Geopark Westerwald-Lahn-Taunus, and are protected as a geotope.

The special ice deposit was discovered in the summer of 1839, when workers were removing stones for a road construction in the boulder field on the southern slope of the Dornburg. They found ice about half a meter below the earth's surface in midsummer. This caused quite a stir at the time and was extensively investigated by the Ducal Nassau State Government. Linde's refrigerating machine had not yet been invented, and ice for cooling food had to be stored in ice cellars in winter. This was probably the reason why J. Troost from Wiesbaden came up with the idea of using this cold and had a brewery built on the southeast slope of the Dornburg. For this purpose, he had two tunnels driven into the foot of the scree slope, which served as ice cellars for the beer. The effect was further enhanced by shovelling snow into the tunnels. But in 1886 the brewery at the Dornburg burned down. In the meantime, however, the refrigerating machine had been invented, and so it was not rebuilt. Instead, a restaurant was built, which is now used by a Wiesbaden youth organization as a youth home.

So, in fact, the tunnels were not created by mining or by Basalt quarrying, which was also done at the Dornberg, but they were created as ice cellars. The first quarry was opened on the northern slope of the Dornburg in 1886. In 1905, basalt was mined in four operations, and at times more than 500 people were employed in the Dornburg basalt industry. In 1927, part of the mountain was designated as a nature reserve. But soon there were economic concerns and in 1938 and 1963 the nature reserve was reduced in favor of the basalt industry. It was not until 1989, when the quarry had again reached the border of the protected area, that conservationists and especially the Westerwald Association fought back.