From the brewer:
“Jopen Koyt is brewed with gruit, a medieval blend of herbs in which sweet gale picked according to ritual was essential. Legend has it that, to avoid its hallucinogenic properties, sweet gale could only be picked at full moon by nude witches.
The spicy flavour is highly complex and smooth. This reddish-brown beer is a reproduction of a Haarlem beer and is brewed according to the brewer’s statute (recipe regulated by the council) of 1407.