I've noticed that if I don't drink any beer during the week, when I go to pour a beer on say Friday night, the tap handles are very difficult to move/difficult to open the tap. It's like I have to "break them free" if I haven't used them for several days. After I put a little muscle into "opening" the tap....then everything works fine for the rest of the night. Any ideas regarding why this happens and/or things that I can do to prevent it...(besides pour a beer every day)??