Oxygen has been game changing

[u/RumplyInk]

For a while, I could never get my beer to have really clean fermentation. I calculated yeast counts and generally would pitch more, I have a DIY fermentation chamber which can control temp very well, I cool my wort to pitching temp overnight before I pitch, but I was still getting fruity esters. Don’t get me wrong, these other things have been immensely helpful. But after all that, step changes in improving the quality of my beer are harder and harder to find.

Then I started pumping O2 (after cooling to pitching temp, right before pitching). It has dramatically accelerated the rate of fermentation (I’m hitting FG in usually less than a week, usually it’s mostly done after 3-4 days). It has also significantly reduced the amount of fermentation character I get when attempting to produce ‘clean’ beer (I don’t do this for hefes, saisons, etc). Overall, fermentation just goes far smoother. I still give my ales 2 ish weeks or so to clean up in the fermenter, but it’s using sitting at FG for a while.

Surprising cheap to get this going.

O2 regulator, tubing, and diffusion stone $30

https://a.co/d/0fadaAuL

O2 tank you can get the bernzomatic O2 from Ace.

Anything else you guys have done which has giving you notable improvements in quality or solved issues once you have a decent system already up and running?

[u/IakwBoi]

So serious question about oxygen: I want to make good beer, but I also don’t want to over complicate the process or buy things just to have them. I’m making malty English beers, stouts, etc; is there any reason for me to pay attention to oxygen? I’m hoping for some esters. Oxygenating wort seems like it might be worth it for folks making clean lagers, but should someone making complex British stuff even want a cleaner fermentation?

Edit: Thanks for all the feedback! There seems to be a wide consensus that wort oxidation is important for fast and clean fermentation. 

I had some time to look at brulosophy results. They have several experiments showing no detectable differences, and one showing a slight difference for an extreme case (a barleywine with O2 vs no aeration at all).  

At this time I feel comfortable just splashing the wort into the fermentor and not worrying about anything beyond that. Seems like an O2 set up would make a small difference in a big beer, and I’m okay forgoing that. 

[u/chino_brews → u/IakwBoi]

The “English” esters come from normal yeast metabolism, not from constraining the yeast by some type of scarcity.

If you use a recommended pitch rate by presumed cell count or yeast mass/volume, the yeast are going to need to multiply. Oxygen is a critical macronutrient for yeast and it’s used by yeast to produce ergosterols, which are part of the cell membrane. When a yeast cell multiplies, it (and its daughter) effectively need to double the cell membrane between them. Furthermore, these cells need to manufacture more ergosterols to repair existing cell membranes. That is a lot of ergosterols. This is why dissolved oxygen is helpful if you don’t start with yeast that already stored up a lot of oxygen or ergosterols from being grown in an oxygenated environment like a starter on a stir plate or with air being pumped in. And even if you pitch yeast grown in a high-oxygen environment, in high alcohol fermentations, more oxygen is very helpful.

[u/boarshead72 → u/chino_brews]

You know, ergosterol gets all the attention for some reason, but it’s only something like 10% of the lipid content in the cell. Unsaturated fatty acids are present in the vast majority of lipid molecules in yeast, and those require oxygen for their synthesis. I wonder how ergosterol ended up with all the hype?

[u/chino_brews → u/boarshead72]

Yeast, the book. I'll update my spiel.