oxygen level in 13 gals

[brewmaster48]

I am oxygenating at 60 secs .05 micron stone, 12ppm for my 1.057 beer 5 gal batch.. Because I am doing a 13 gal batch do i double the time to 120 secs. this is the first time using pure o2

 

[Dcpcooks]

It's about oxygen levels which are hard to estimate without a flow meter. I usually do 1 min for my 1/2 bbl batches at normal gravity. You don't want to over oxygenate that can cause acetaldehyde.