It's the salt-seether's responsibility to ensure that the saltwater in the iron pans is maintained at the correct temperature. He does this using a wooden rake which he pulls through the water. It's also the salt-seether who describes his trade and the history of salt on Læsø. He does this completely free of charge for all those wishing to listen on the stroke of every HOUR from 10.00-16.00 from 1 May til 1 October, as well as at Easter and during the autumn half-term holiday.
Very salty groundwater
Today, as in the Middle Ages, the brine is recovered from wells dug at Rønnerne. A combination of geology, winter storms and a dry climate mean that very salty groundwater is formed. On several occasions during the winter the seawater floods the flatlands and in the summer months there's a high rate of evaporation from the sandy surface. At a depth of approximately 2 metres down in the sand the water meets a solid layer of blue clay, which prevents it from seeping down any further, so that it remains near the surface and evaporates. The water reaches a salt concentration of up to 15 per cent. In comparison, the salt concentration in Kattegat is around 2-3 per cent.