Oxygen - The Sometimes Enemy

The Point

  • Oxygen can ruin a good beer in no time
  • Yet, we need it as well!


How do we stop it from being the enemy

Dissolved Oxygen

  • A measure of how much Oxygen is infused into your beer throughout the brewing process
  • O2 is everywhere in the brewing process
    • In your water, malt, hops, yeast, sanitizer
    • Every transfer can add O2
    • And lastly packaging and service!

The Good

Why You Need Oxygen

  • Yeast use O2 to create sterols
  • Sterols help create strong, flexible cell walls
  • Strong yeast are solid performers
  • Maximize growth in starters, but you'll still get growth in fermenter.

Oxygen Needs

  • Starters
    • O2 Injection
    • Stir Plates
    • Shaken Not Stirred
  • 8-15 ppm needed for fermentation
    • Atmospheric air provides ~8 ppm
    • Bottled O2 can provide all the O2


  • ​​​​​Or use dried yeast or a slurry


Don't use Olive Oil

The Bad


  • Research shows oxidative damage occurs during brewing 
  • Mash/sparge O2 interacting with malt compounds
  • Relatively small concern for homebrewers.
    • Many other processes to fix first!
    • Less impactful in non-pale lager situations
  • Look up LoDO practices if you need a new reason to tear your hair out

Post Pitching

  • No active yeast, means no Oxygen uptake
  • Oxygen in solution is waiting to do damage
  • O2 Ingress Possibilities
    • Dry (or missing) Airlocks/Leaks/Sanitizing Solutions
    • Dry Hopping
    • Transfers
    • Bottles/Cans/Kegs/Lines

Packaging Issues

  • Kegging/Bottling/Canning
    • labor intensive
    • prone to mistakes
    • our best chance to introduce cold side O2

Surface Area Matters

Cans Are Hard

Properly packaged cans are great


It's hard to properly package in a can


Sloppy packaging will kill any beer

Cold Side Oxygen Impact

The Preventives

  • general rules
    • keep beer cold
    • don't touch the beer needlessly
    • flush oxygen as much as possible
  • Hot Side Preventives
    • chemical additives like Brewtan-B, Ascorbic acid, MBS
    • ingredient choices like roasted barley
    • old advice of things like cinnamon
    • processes: get the beer chilled fast, don't splishy splishy splash
    • don't sweat the hot side nearly as much as the cold
  • Fermentation preventives
    • pitch lots of healthy active yeast - they'll take up oxygen
    • don't let the airlocks dry up
    • if you're open fermenting, don't let the krausen fall without getting an airlock in place
  • dry hopping
    • use pellets to reduce entrained oxygen
    • some brewers flush hops with CO2 and use dry hop devices to reduce oxygen. (more a hazy concern or a gear lovers thing)
    • fewer additions is better in this regard
  • Transferring/Packaging preventives
    • In general, transfer as little as possible.
    • Consider flushing the lines with CO2 (drew uses jumper lines for instance
  • Bottles and Can
    • yeast conditioned beer gets a leg up here because yeast scavenging helps
    • "Slow is Smooth, Smooth is Fast"
      • Don't rush around, do things smoothly
    • forced carb beer
      • sanitize and make sure the package drip dries throughly
      • CO2 flush
      • fill smoothly from the bottom, generate a little foam - beergun, counter pressure, tap-a-cooler can seals
      • seal quickly and throughly (O2 scavenging caps should be sanitized last second
  • Kegging Preventives
    • sanitize the keg with a full keg of sanitizer
    • push the sani out the liquid post with CO2 (fully flushed keg)
    • make sure the sanitize is truly out of the keg completely.
    • flush your transfer line
    • push beer into the keg liquid post if possible. if not, crack the keg top and cover with foil, fill from the bottom
    • lid and flush with my CO2
  • Storage Preventives
    • Keep your beer cold. 
      • beer stored at 70°F ages ~10x faster than beer at 40°F
  • Things Not to Do
    • Wax doesn't really do anything to prevent O2, it looks pretty and can be annoying to remove

In Summary

  • Oxygen at pitching time
  • Avoid it elsewhere
  • CO2 is cheap, brew time is expensive
  • Keep Things Cold


Oxygen - The Enemy

By Drew Beechum

Oxygen - The Enemy

The Simple Rules to Making The Best Beer Possible With Minimal Fuss.

  • 117