I have read many times on CC that I can add flavorings,syrups and coffee creamers to WASC to change the flavor. So, I added caramel macciato (sp?) liquid creamer in place of the other liquid (water I think). Kept everything else the same. While the flavor was extremely good, it made the cake very dense. Normally this wouldn't be a problem but, I made the cake a rainbow and the cake didn't rise like normally being so dense so, the colors of course weren't as nice - sort of all smashed together.

What did I do wrong? Should I have put in 1/2 water and 1/2 creamer to thin out the creamer? I really would like to continue doing some experimenting like this with the base WASC.

Which WASC recipe are you using?
The use of creamer should not have effected the outcome.
What brand of mix are you using? That might have been the difference.
I have used nectors (fruit juices like apricot) w/o a problem. I don't see where the creamer was what caused the problem.

The recipe that I always use is:

http://tinyurl.com/2cu8s4

I replaced the water with the coffee creamer.

There's only so much "doctoring" you can do to a cake mix/doctored cake mix before it fails (as there is a science to baking).

Too much sugar, fat or leavening will cause a cake to sink in the center. In your case, it was too much sugar!

Handy cake troubleshooting charts:

http://tinyurl.com/2p5bdu

http://tinyurl.com/32goqe

http://tinyurl.com/6c745g

http://tinyurl.com/6lpjww

It has also come to me, that a lot of members seem to define "dense" as fudge brownie-like, which to me is just gummy... When I say "dense" I mean "like a pound cake."

HTH

P.S. When it was very popular on CC to use the flavored liquid coffee creamers in everything cake, there were a lot of disasters when replacing all the liquid with the liquid creamers. Depending on brand (Int'l Delight), no more than 1/3 of the liquid should be replaced with liquid creamer.

Thanks for the links! Regarding my cake: it just didn't rise but, it wasn't noticeable since I'd used the bands on the outside of my pan. But, one it was cooled I noticed it right away. On the cooling rack, though turned upside down, it was sort of sunken in the middle. It wasn't really gummy, just not as light as normally.

........Too much sugar, fat or leavening will cause a cake to sink in the center. In your case, it was too much sugar! .........

Yeah, that was my 1st thought also. Just forgot to mention it Glad you covered it.