These separate the water at bottom quickly when held vertcal briefly. Squirt water out into waste jar, then I squirt the oil in oil jar. Repeat a few times and done. It helps to use a tall narrow glass, but these do well also. EDIT: If you see the black relief on top. it has 2 positions. 1 is to vent so you can open quickly, but when cooking it should be in "Pressure" position, which is basically closed unless safety relief pressure is overcome. Only a safety, should not vent when in PRESSURE position, during cooking/decarb.
We use the OXO turkey baster for the same application (sucking oil) and it is wonderfully efficient...