Gas in oil

Stupid question, but I´ll ask it anyway. :angry7:
Drained the motor on the oil ...and...
Is there any other way than by smelling to determine if I got gas in the oil?
It does smell supicious but I´m not sure.
I don´t want to ruin the Royal Purple oil I´m about to change to.
Did a experiment (using a funnel and a stopwatch) by comparing the viscosity of the old oil and new 15w-40 oil.