Pool of dwarven wine

A giant pool of dwarven wine is slowly growing on the outside of my fort... No idea where this is coming from and it's not disappearing.

https://preview.redd.it/o5amrp9uzmoe1.jpg?width=1833&format=pjpg&auto=webp&s=269d09e0fddd78a34a99a3653eb453f2bc776569