Guinness is not to be discussed in the same context as real beer. It is made from watered-down burnt unmalted barley and is low in hops. Its head and frothy texture is achieved entirely by mechanical means via nitrogen gas and a device in the tap. Good for you if you like it, but there is real beer out there too! In the bad old days, when many a pub had no decent cask ales, Guinness came in handy as something at least tolerable. That role has greatly diminished.