Half and half

Half and half refers to various beverages or liquid foods made of an equal-parts mixture of two substances, including dairy products, alcoholic beverages, and soft drinks.

In some cafés in Brussels, a "half en half", Dutch for "half and half", is a mixture of white wine and champagne." Originally, it was a mixture of two different typical beer types from Brussels: 50% lambic and 50% faro."

If you order a "half and half" in a Copenhagen bar, you will get a mixture of dark beer and pilsner (lager). The dark beer is a Danish version of an Imperial stout-type beer - in Denmark simply called "porter", which is a little sweeter than a Guinness.

In Ireland, a half and half is a combination of Guinness draught and Harp or Smithwicks Ale, with the Guinness in a layer on top.

In Britain, a half and half may also mean a mixture of mild ale and bitter.

In the North East of England, a request for a half and half would more commonly produce a combination of Scotch ale and India Pale Ale (IPA). This drink fell from favour when the Scottish & Newcastle brewery were obliged to sell many of their tied public houses and McEwan's Scotch and IPA disappeared from public bars across the North East.

In Canada and the United States, capitalized Half & Half is Guinness draught and Bass Pale Ale. A lower case half & half is a generic Guinness draught. Black and tan is any lager or ale that will support the Guinness draught, although some Irish-themed bars shun the term for its association with the Black and Tans. In the U.S., the terms (Half and Half, Black and Tan, etc.) are not actually interchangeable. All of the versions start with Guinness Stout. "Black and Tan" refers to Guinness and Bass. "Half and Half" is Guinness and Harp. Guinness and Smithwick's is a Blacksmith.

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Wikipedia