http://www.beerwhich.com/tester/loggedIn.html
It's a static prototype but you can start typing in a beer name and select one of the options from the predtive text box. After doing so try clicking "I'm Drinking."
At that point we add your beer/timestamp to the feed, and you can decide to add more details or not in the brown second step.
Let me know if you find this to be intuitive or not.