The method to refining pig iron into wrought iron was brought to Sweden from Lancashire, England.The charcoal and the compressed air introduced, created the necessary temperature. Oxygen from the air as well as from the slag mixed into the molten iron reduced the carbon content. In one hour 165 kg of low carbon iron was refined and removed from the hearth and brought to the hammer.

The forgemen, two at each hearth, worked in 6 hours' shifts making every second heat each, then rested the next 6 hours. Food was brought by their children, many stayed at the forge throughout the week until Saturday. On Sunday night the working week started all over again.