*forgets ginger beer*
Mmm, birch beer. I've only been able to have it a couple of times, but damn it was good.
Hmm, seems like a cola cap you'd actually want to get bubbles in for carbonation.
What really needs to happen though, is a Mountain Dew cap.
Light acid green foam layer, bright acid green. (And then carve some caps out of cheetos to go with it, except keep them about 20 billion miles away from the keyboard.)