I don't have a plain CD, but I tried a CD-RW and the ability to leave it appendable was not available. I'm not sure if that is related to CD-RW or if the feature was dropped in Mavericks.
Check the More Like This links on the right.
The process previously was to create an image of the folder that held the things you wanted to burn. Then, in Disk Utility, burn the image to disk and check the box to leave it appendable. This was only available for CDs, not DVDs.
You might try some other burning software.