I recently replaced my glass carboy with a 20 liter Spiedel plastic fermenter. One problem, the unit is opaque so I cannot read the hydrometer. After one week fermenting at 50 degrees i opened the fermenter and dropped in the hydrometer (sprayed with star san) to get a read. The container was open a half minute, but now I am concerned if that brief time allowed too much oxygen to enter. I want to check the hydrometer again but don't want to risk spoiling my lager.
Does this brief exposure to oxygen pose any risk?
Thanks,