i find it seems to thin out a little and then thicken and then thin. if you keep it moving in your mouth, it should first thicken and then eventually thin to like water. that is when it is done, when it has lost all viscosity. i dont think 3 minutes is long enough. it wont hurt to spit it out then, but it is probably a waste of oil. experiment with different times until you are confident of what you are doing. i have gone as long as thirty minutes without filling up the oil. my diet was very clean and raw on those occasions.