This is a serious homebrew discussion! While I’d agree that hot side aeration is an important topic, I’m inclined to believe that there are many more low hanging fruit items to consider for home brewing lagers. For many of the temperature set points your brewhouse will be at, 1 ppm will be close to saturation levels requiring intent or incredibly poor design to incorporate that much air into the hot liquid.
Hitting 1 PPM even on the cold side can at times prove challenging. In our brewery, knocking out cold(which oxidizes easier) fresh wort into an open oxygen rich fermentation tank tends to yield less than 1PPM dissolved oxygen. That’s why introducing oxygen directly into the wort stream is so important for yeast health.
That being said, hot side oxygen should still be a concern. We operate an automated 60 barrel brewhouse. Hot side aeration considerations were built into it’s design. For example all product is transferred from and to the bottom of each tank. This is particularly important for us since we are continually transferring our mash when we decoct. All tanks are sealed and the transfers are controlled by the brewhouse software.
Oxygen is always going to be the enemy of beer. Anything you can do to limit oxidation is important. Can I taste the difference between .5 or 2 ppm hot side aeration? I wouldn’t be so bold to say I can. I have no doubt though that the best lager breweries are taking this into consideration when brewing.
The main decision for investing in the horizontal tanks was for planning the production of Copper Legend. Time is a key ingredient in lager beer, and unfortunately Copper Legend production falls in our busiest production time. The horizontal tanks allow for production flexibility and are also for great long term storage of beer. Lager yeast tends to drop bright regardless of tank design considering the time in tank it has. Having a large surface area between the yeast and beer after it falls is more important than just the fact that yeast in horizontals brighten up in storage faster and easier.
The majority of our standard upright tanks are still fairly unique. All of our large fermenters are very wide short tanks. This helps to keep some of the similarities of more traditional lager tanks. Generally the height of the non cone portion of a CC is 2x the length as the diameter. Our tanks are only 1x the length of the diameter.
Yes, all the mash is pumped tank to tank form the underside of the tanks through special piping designed specifically for this purpose.