In the past weeks two of my followers have pointed me to a paper released by the folks from the German Brewing Forum. That paper talks about low oxygen brewing and how very low oxygen levels (so low that even very detail oriented brewers will have to change their brewing technique to achieve them) are responsible for what we have been calling the Elusive German Flavor in beer. That delicate malt flavor with a subtle background of fresh hops.
I myself have not been able to test any of this but am very intrigued to do so after reading through the paper. The main points are that one needs to deaerate the strike and mash sparge water, use sodium metabisulfite as an additional scrubbing agent and be very careful with doughing and any oxygen uptake later during the brewing process. A DO (Dissolved Oxygen) meter helps with keeping track of the O2 levels throughout the process.
If you think this is the HSA (Hot Side Aeration) discussion all over again, you are somewhat right with the caveat that there is new evidence and a new theory. This theory postulates that the current standard home and craft brewing process already allows for enough oxidation that additional splashing of the wort does not do any noticeable change. As a result HSA experiments have shown inconclusive results so far.
I have heard that this started to spark controversy and I can see that. If the authors are correct, and many seem to have been able to repeat the results, brewers will have to take a closer look at their brewing process and possibly equipment if they want to achieve these results. But keep in mind that not all types of beers are expected to benefit from this. There are many excellent beers, especially craft beers around the world, that are brewed in conventional brewhouses without a low oxygen process. It’s more along the lines of decoction where an more elaborate brewing process is used for some beers to achieve the desired flavor profile.
At this point we have something new to try and to look into and need to see how this develops over time. Especially as these beers are showing up in competitions and we can see less biased results.
An anecdotal observation that supports this is that craft brewed beers in Germany (usually brew pubs) lack that delicate flavor that many commercially brewed beers in Germany have. Those commercially brewed beers are more likely brewed in a low-oxygen brewhouse.
Here is a link to the paper: On Brewing Bavarian Helles: Adapting to Low Oxygen Brewing