I've been thinking about this question for a while now after having initially read quite a bit about American lager brewing and then delving into the history of Swedish beer brewing. Reading about the American history of brewing it seemed as though 6-row barley malt was more or less an exclusively American grain, which found a suitable complement in corn which was also grown on the continent. But when I started reading about the history of Swedish beer brewing, I came across claims that 6-row barley had been the dominant type of barley in Sweden up until the late 1800s when British 2-row breeds were introduced to Sweden, along with the pilsner-style of beer. 2-row barley was found in Sweden prior to this but it was rare compared to 6-row, and it was distinguished from the common 6-row by the name gumrik, though it sounds as though this 2-row type was of a primitive sort compared to modern barley. Meanwhile it seems as though 2-row barley has been the backbone of British brewing for some time, and also German brewing going by some sources, and this makes me wonder if in fact the historical footprint and geographical spread of 2 and 6-row barley is more complex than we commonly imagine. Based on the knowledge that 6-row was the standard barley grown in Sweden for centuries, I can't help but wonder if the same was true for Denmark and what are now the northern parts of Germany. I've read about Denmark and northern Germany being pioneers when it comes to adjunct brewing (with the north Germans being particularly fond of rice as an adjunct) and I wonder if in fact the use of adjuncts in these areas was a direct result of 6-row barley being the primary crop there, which might have necessitated the use of adjuncts to produce a clear beer once pale pilsner style beers were being brewed there. That's simply a hypothesis on my part, as an attempt at explaining why adjunct brewing became so popular in both north Germany (prior to the reinheitsgebot being extended to the unified German Reich) as well as Denmark. Even though Swedish farmers and brewers switched to 2-row in the late 1800s the brewers still ended up using considerable amounts of corn-adjuncts by the mid-1950s, similar to Danish brewers. I guess this could be an indication that 2-row barley could have been the major type of barley in northern Germany and Denmark in the latter part of the 19th century, and that adjuncts were used simply as a flavor "enhancer" (producing lighter bodied/tasting beers). Still I find this to be an interesting topic, and I wonder if any of you on this forum have any additional information or theories which could shed some light on this matter.