I'm sorry but i still disagree. While preserving the crema to the top of the cap my help with the aromatic profile of the drink, as the cup if lifted, then tilted to allow the beverage to enter the mouth, the foam sits on top while it is the milk that enters the passage. I'd estimate at a ratio of 90% milk to say, 10% foam actually entering your mouth. This is why usually the rosetta (or not) is still left at the base of the cup when you've finnished drinking the cappuccino. The foam, for the most part, is the last thing consumed. Either way, even if you do beleive i'm wrong on this point, the original question related to why there was btterness in the cap and ofcourse if it was normal that it exists. Obviousely it is not normal, and i highly doubt that the main or even predominant reason for summercrema's cap being bitter is whether or not the crema is elevated to the top of the beverage, especially considering that i imagine most of his caps were covered in chocolate. I'm sorry, but i just think it's misleading (esp with your level of expertise) to offer this explaination when it's entirely more plausable that the bitterness is the result of one of many, many more factors.