The cap should be tightened enough so that the serrated part at the base of the tube screw section is no longer visible. An insufficiently screwed cap will not open a large enough hole in the hermetically sealed part of the tube
The cap should be tightenedenough so that the serrated part at thebase of the tube screw section is nolonger visible. An insufficientlyscrewed cap will not open a largeenough hole in the hermetically sealedpart of the tube