There are three types of music files:
1. Lossy compressed: These files have some bits thrown away (lossy) and undergo compression (similar to a zip file) to reduce file size e.g. MP3, AAC, etc. These typically have the smallest file size, and most of these formats retain metadata (song name, artists, etc).
2. Lossless compressed: These files contain all of the information of the original CD (lossless), and are compressed to reduce file size e.g. FLAC, ALAC. etc. These file types are larger than lossy compressed files, and store metadata.
3. Lossless uncompressed: These files contain all of the information of the original CD, and are not compressed e.g. WAV, AIFF, etc. These formats have the largest file size, but only AIFF retains metadata and tags. WAV does not, as I've described above.
CDs can be burnt from all of the above file types which has nothing to do with whether they include tag info or not. To better describe how WAV files do not store tags, download a different player for your Mac (Play, Max, etc.) and play one of your already ripped files. You'll notice that none of the song info will be available.