Raimey,
The "German method" mentioned in this article indeed came from what is today Germany and was basically what replaced rather crude furnaces that made osmund pig iron (and hence sometime called osmund furnaces). FYI, osmund pig iron was hacked into chunks having defined weights. These chunks were packed into specific sized kegs and often used as valuta in trade and other business exchanges. These chunks were reported to not have been further processed in early Sweden, until Gustav Erikson (today called Gustav Vasa) brought in German iron workers. Before that, osmund was shipped to Germany, processed and Swedes bought tools, implements, etc. from Germany. Bad economic situation that Gustav Erikson changed. Bringing in Valloner was later step in same direction.
Locally, in Uppland region of Sweden, the German method was replaced by Vallon method, which used less energy and produced much higher quality iron. However, German method continued to be used because it produced iron suitable for many uses. In various places, Lancashire method did replace older method, be it German or Vallon.
Next time I am back in Sweden I hope to visit some non-Vallon järnbruk, as well as some ancient Cu mines, etc.
Niklas
