We raised the minimum age to drink Keizer Karel to 35 years. Quite literally, even: we banned

our beer for everyone under the age of 35. A congenial message that we spread via billboards,

POS posters and radio commercials.

But in order to really prohibit the less mature person from actually drinking it, we made sure that

every bottle of Keizer Karel had a combination lock. We called it 'the drinking lock'. A test, to find

out if you really were old enough to drink Keizer Karel. If your answer was correct, you killed two

birds with one stone: you had the right combination for the lock, and your bottle of Keizer Karel

came free of charge.

During the campaign a staggering 3000 bottles per hour were consumed in pubs and other

licensed premises. The number of website visitors grew by 86%.