On occasion, the straw in the cap becomes pinched. Many times you can actually see where the straw has become stuck together internally. You can fix this very simply by doing the following:

-Open the cap so the straw is sticking up.
-Grasp the straw with your thumb and index finger, at the point where the straw exits the cap.
-Gently pull the straw out slightly, while at the same time rotating the part of the straw that comes in contact with the cap, between your finger and thumb.

This should open the straw up, allowing you to use your new Sport Berkey®.