When brewing beer, it is important that yeast have a good supply of oxygen available during their first phase of life. When you boil the wort (unfermented beer), you remove a lot of the oxygen. Homebrewers can add more O2 by vigorously shaking the wort for a few minutes before adding (or ‘pitching’ as it’s called in brew terms) the yeast.

While this is usually adequate, it’s quite tiring trying to jiggle 5+ gallons of liquid around. Plus, air mostly nitrogen, so it’s not the most effective way of doing it. This is why many brewers use bottled O2 and a beer stone (usually a stainless steel tip with tiny pores that break up the oxygen) to oxygenate their wort. A 15–20 second blast of pure O2 can provide better oxygenation than shaking for 5 minutes.

Since my last brewing session was a complete failure, I plan on brewing again. I asked another brewer at work if I could borrow his O2 kit and he brought it in today. On the O2 canister label it says

WARNING:
This container and byproducts of the combustion of its contents contain chemicals known to the state of California to cause cancer, birth defects or other reproductive harm.

Ladies and gentlemen, this is a label on a canister of oxygen. You know, the stuff you breathe every second of your life. The container itself I can understand, it’s some sort of metal alloy and could contain something that, if eaten by the pound daily, would cause cancer.

But the combustion of the contents? Excuse me?

So now we should all just exhale and hold it since oxygen will cause cancer or reproductive harm. Granted you won’t last long without it, I guess in California that’s an acceptable risk.