Take a bottle of English beer , it will amuse the Polish people who will think its water compared to the Polish stuff....
I've started drinking Polish beer over here, and I'm not the only one judging from the fact that Tyskie is now one of the top 10 selling brands in the UK (which can't all be down to Polish immigrants after a taste of home!) Give us an option that's stronger, cheaper and tastes better than most English beer and what do you expect?
Best of luck on your first trip to Poland!