I did some more research on the effects of Dissolved Oxygen (DO) in the strike water and once again, although there are many detractors, most agree lower DO levels will result in a fresher and fuller malt expression of the grains because of less oxidation during the mash.
Brulosophy did a recent Q&A podcast that addressed several interesting lager-related topics, one of which was "Yeast Oxygen Scavenging" (YOS). This was something I've never heard of before.
So apparently there are 2 fairly easy ways to make sure your DO is near zero before you mash in:
Pre-Boil Strike Water - see my previous post
Yeast Oxygen Scavenging
The Modern Brewhouse reviewed some experiments for these 2 methods and they both seem to take the DO levels to 0 ppm.
Pre-Boil
The pre-boil of your strike water essentially took the DO to zero once the water hits 212F, as the experiment revealed:
As temperature raises, DO has an inverse and falls. When 100c (212f) is reached DO hits terminal (0 ppm). This took roughly 24 minutes in this test. Obviously the 11k watts of power had a great effect on time and efficacy. None the less, this is a very valid method for the dexoygenation of water.
The DO should remain at essentially zero for 3-4 hours. In my opinion this is the simplest method but requires more time to cool the water back down to mash in temps
Yeast Oxygen Scavenging
In this method, simply add sugar and Baker's yeast at the dose of 2g / gal. After 30 minutes, the DO will be zero and remain there for up to 4 days! It does apparently make the strike water slightly cloudy but doesn't have any effect on the brewing water after the mash. You can also dose at 1g / gal then heat the water up to 115F and wait 30 minutes to get to zero DO.
Strictly speaking from an energy and ease standpoint the default 2g/gal YOS dosing is pretty hard to beat. Dose and wait 30 minutes (to 4 days!) and you are set. If you want to accelerate 2g/gal dosing, heat the kettle a bit.
If you want to cut back on yeast and sugar amount in the water, 1g/gal is a great alternative. You can wait a little longer (>1hr), or slightly heat the kettle to 35-40c (90-115F) and have very fast (<30 minute) results. From my testing of the YOS, I have seen the “murky water” to have zero affect on mash clarity, or have pH move around much.
Wow, crazy idea but I guess the yeast uses up whatever oxygen it can find to start fermenting the sugars in the water. Great idea!
After looking at these options, I will likely start using the third method, adding 1g/gal yeast and sugar to the water before brewing, heat it up to 115F, wait 30 minutes then raise to mash-in temps and proceed with the brew day. Seems like a fairly simple way to preserve the malt freshness..... perhaps the whole thing is crazy and a waste of time, who knows ;)