There was this little thing in your fermenter called AIR which when you put beer into it, and snapped an airlock on it, you displaced, and the airlock is doing what it's meant to do, act as a VENT to let any EXCESS gas, be it co2, or in this case OXYGEN, out of it. Because that's what an airlock is, a vent, a valve to release excess gas, and keep the beer off the ceiling. It's not an accurate gauge of fermentation, because gas comes in many forms, such as oxygen that may be present in the solution, or gas can expand and contract due to changed in temp or barometric pressure.
Like my snazzy new avatar? Get Sons of Zymurgy swag, here,
and brew with the best.
Revvy's one of the cool reverends. He has a Harley and a t-shirt that says on the back "If you can read this, the bitch was Raptured. - Madman
I gotta tell ya, just between us girls, that Revvy is HOT. Very tall, gorgeous grey hair and a terrific smile. He's very good looking in person, with a charismatic personality... he drives like a ****ing maniac! - YooperBrew