Munich Mayor Dieter Reiter opens the world’s largest folk festival on Saturday when he taps the first barrel of beer at noon (1000 GMT) on Saturday to officially start this year’s Oktoberfest. Reiter, a Social Democrat, will hand over the first litre to the Bavarian Premier Markus Söder of the conservative Christian Social Union party. The two are very far apart politically, but politics will not be on the plate – at least not now – as Reiter and Söder are expected to toast the start of the two-week long drinking festival which ends on October 6. Only after the toast will the beer start to flo…