I plan to do this as my next side-by-side for an Alt. I actually have a pretty strong opinion for removing the Kräusen and wonder if I'm right with that.
Clean non-lingering bitteness is a hallmark of German beers.
I once read an ad in an issue of Brauwelt International where foam control was advertised as limiting the loss of bitterness. Obviously this was targeted at non German brewers since foam control is not allowed in German brewing.
May be...but I have found through blind tastings a clear distinction between Authentic German beer and American examples of German style beers in the hop character and hop flavor profile...particularly in the fest beer examples.
There seems to be a refined bitterness and a spicy flavor attributed to the German style fest beers as opposed to a more pronounced bitterness but yet cleaner hop flavor profile attributed with American examples of German Fest beer.
I really believe the clean but yet spicy hoppiness in German beers is primarily attributed to the regionally grown German hops that are used ...Hallertau Hersbrucker, Spalt, Tettnager and Saaz as opposed to the American grown examples of German seed hops.
The following link outlines the real differences in the regionally grown hops and how they affect the bitterness and flavor of beer.
The alpha-acids content of the German variety Perle, for example, is 3-4% higher in Oregon than in Bavaria where the hop was developed. The U.S.-bred Nugget regularly has alpha-acids levels of 11-15% by weight in Oregon and Washington but only 10-12% in Germany, despite good cone production in both locations. Cascade, selected in Oregon, generally contains more alpha than beta acids when grown in Oregon but slightly more beta than alpha acids when grown in the Yakima Valley of Washington. Although the total level of alpha acids may fluctuate somewhat between seasons and locations, the alpha-acids composition of most varieties, as indicated by the relative proportion of major alpha-acids components such as humulone and cohumulone, changes relatively little, regardless of area of production or season .http://brewingtechniques.com/library/backissues/issue1.1/haunold.html
Kai...I am interested to learn the findings of your Krausening experiment.