Western Poland used to be German, but all the Germans left/got expelled. After WW2 it was resettled with Poles from Eastern Poland, nowadays Ukraine and Belarus. Which makes traveling from Berlin to Poznan or Wroclaw an interesting experience. Directly at the German-Polish border, you'll enter Eastern Europe, then when you arrive in the mentioned cities, you're suddenly back in Central Europe.

Also, you'd be surprised at how widespread pickled herring is in Bavaria. Herring has been a trading good for millennia in Europe, was and is still consumed in the winter months in Bavaria. You can easily get a "Fischsemmel" at the Oktoberfest in Munich. Bavarians also used to pickle everything for the winter: cucumbers, beets, cabbage, beans.