1. Muttered softly so as not to distract or startle coworkers with perceived aggresion
2. "Don't talk to me till I've had my coffee" clearly states workspace boundaries with humor & casual, relatable firmness. "
3. Constant repetition to emphasize importance of not talking to you until you've had your coffee while also making it impossible for coworkers to get a word in edgewise. If done properly, you should be able to get from popping the coffee into the kuerig to drinking it without anyone able to say anything to you.
Be sure to make a lot of eye contact with whoever is in the breakroom during this ritual-- this communicates respect & confidence. If there is no one in the breakroom at all, go ahead and mutter "don't talk to me till I've had my coffee" to yourself. It's good practice and if anyone overhears you, they'll be sure to take you a lot more seriously.