I'm a believer in trying to reduce O2 contact where feasible and reasonable. But it's kind of ironic that hopfenundmalz is IN Germany and just raved about (among others) a small family brewery with a copper laden system that makes an amazing, award winning Dunkel. Maybe he and the Germans have poor palates.
The two kettles are Stainless, the chains on the stiring arms that drag the bottom are copper, a big one followed by a small one. He mainly makes a Dunkel.
We spent two nights in Petting, and toured Schönram. That is a very highly automated modern system, all SS. There was a water treatment plant, and what I got from the guide (seemed to be a retired Brewer), was that the water was de-aerated. This is a packaging brewery, so they will use de-aerated water for the bottling line, the boiler, and the brewing. The mash came in though the top into the mash tun, a you could see it through a sight glass no idea it they were mixing under N2. They were filling and mixing the mash ton, while a boil was underway - so no decoction. The guide talked a lot about the different temps in the step mash. The pellet hops had been added to what looked like 3 hop backs, but these were plumbed in a loops to the kettle, and it sounded like the wort was recirculated through them in 3 timed additions. They had a big whirlpool and chiller. A flotation tank was noted on the CIP manifold. Fermentation was all open. Lagering tanks had spunding valves.
The Helles, Zwickel, and Pils from Schönram were very clean.
After that we went to Traunstein, hope to tour the Hofbäu Traunstein brewery tomorrow.
I am in Munich Tuesday and Wed. Weihenstephaner was booked 2 months ago - it is just before Oktoberfest. Will see if there have been cancilations. Hope to hit the English tour at Ayinger on Wed.