In the book Kiefer says adding coffee to your WI is no problem because the heat is not high enough, and doesn't last long enough. I'm adding a small amount of WI to my coffee, and Wiki states that the required temp is 72+ degrees celsius, which my coffee definitely is. Does anyone know how long it would take to denature about 7g WI in near boiling coffee? I've been adding a little bit of cold water to the coffee before the WI, but is it really necessary?

That's a good question. Can't say for sure.  This is a subject I'm interested in doing some research on, so I've bookmarked this thread to come back when I know more.