A street beer is a beer that you take with you on a trip, obviously walking, to the store, pub, match, church, etc. This beer helps you get through all the mouth-breathing wankers that you may encounter on your trip. It also gives you that "running start" before you enter the pub or match. Also it may save you from that terrible dred you get while in church or the store. Upon arrival you dispose of the bevvy and access the institution. This maybe the answer to being infinitely cool. (Enter Shikari, 2009)
"Hey mate, you better toss that street beer before you go into the pub. Otherwise Daisy will kill ya."