Like the other posters stated, you are going to have to keep a very close eye on the dog and its stools. The dog could have a blockage or impaction from the beer cap with serious consquenses. It can require surgery to remove it. I would talk to my vet and seek there advice as well.
He's your friend,your partner,your defender your dog.You are his life,his love,his leader. He will be yours faithful and true to the last beat of his heart.You owe it to him to worthy of such devotion