Originally beer was cloudy, but around 2000BC an anonymous fisherman took his beer out fishing with him in the traditional carrying vessel: a fish's swim bladder. Normally Egyptian fishermen would drink their beer first, then fish, but this particular man did some fishing first, leaving the beer till later. By the time he got round to drinking it, it had become clear.
From then on, the swim bladders of fish (usually sturgeon) have been the traditional method of getting beer to clear.
And in case you were wondering, Caskman is holding the Egyptian hieroglyphs for 2000 jugs of beer.
This year's logo was designed by Claire Zwozny, an art teacher in Wyndham, Norfolk.