Saying it on meta instead of in comments...
Awarding a bounty by criteria such as vote counts, random selection, or alphabetic ordering of answerers' user names, is better done silently without announcing it. Anything vote-based can distort the voting, refusing to evaluate the solutions on their merits distorts the signal from the bounty, and some answerers would have not necessarily participated if the selection method were stated at the beginning.
The above is inspired by several recent bounty threads.