A very interesting visual explanation of decoction mashing from a 1930 German film with a bracing soundtrack. It's actually a pretty good instructional piece on basic brewing principles just as the arse was starting to go out of the whole Weimar Republic thing. Hans Neuberger made other films but nothing as jam packed with so much sheer dual mash tun decoction action. And thrill to candle based tension at around 8:45. Never saw that coming.
Is there any hint as to which brewery this was? I could not make out the words on the barrels during the cleaning and filling stages. Jay didn't get any further than me back in 2009. You can see larger format versions here.