By default, Tomcat v7 was logging everything nicely to the catalina.out. When it got too big, I have removed it. Since then, the log file doesn't exist.
I have tried creating it manually, but it stays there untouched.
Catalina out file is created during the tomcat starting. The reference of the file is hold in the tomcat until the server is stopped. When you restart the server Catalina out will be created again