title_body: Decreasing foam in over-carbonated beer
upvoted_answer: Soap is absolutely the worst thing you could do I guess :P.
  Sometimes I notice that badly dried glasses (with soap rests) produce more foam...
  In general, make sure your glass is spotlessly clean. You could then either leave it dry or make it a little wet, works sometimes...
  Keep your glass diagonal to make sure the liquid touches the glass almost parallel to the glass' inner side.
  Then when pouring, make sure you have a slow and fluent ray of beer that doesn't splash out of your bottle.