I brewed a 5 gallon Irish Stout Extract kit about 5 days ago and today while checking the temperature on it, I realized that I accidentally filled the carboy up to the 6 gallon mark instead of the 5. I was hoping to have this ready for St. Patty's weekend. Is there anything I can do to help this? I already searched and read about possible head retention and less ABV, anything else I should worry about? Will it taste somewhat decent?