There are a number of tutorials on how to “Create an OS X Mavericks Installer Drive” out there. The essential procedure is always the same but quality of the tutorials matters a lot.

What I ended up following was Create an OS X Mavericks Installer Drive in 4 Simple Steps from OSXDaily.
The only thing that didn’t work for me as described is that the installer didn’t ask me whether I want to update or remove the existing Mavericks installation. So, I booted to Disk Utility and erased the existing partition first.

Apple’s official documentation is in OS X: Installing OS X on an external volume . What is misses in contrast to the OSXDaily article is the helpful command line option for unattended installation.