Which types of beer are commonly used for half-and-half beers? Which types of beer are commonly used to create half-and-half beers?



In frequent recipes are only beers of contrasting colours being used (like pilsener vs porter or pale lager vs stout) or other combinations are being commonly used too? What are some of the most popular recipes?
In a Half and Half (also known as a "Black and Tan" in certain locations), the primary factor will be the density of the two beers -- one beer must be of a lesser density than the other to stay afloat.  Contrasting colors are used for visual effect; otherwise, how might you know one was floating?

Common recipes involve floating the less dense Guinness over a Bass, or a Guinness over a Harp Lager.  Its Guinness' particular light density that makes it a good candidate for so many half-and-half style recipes.