Basi refers to the traditional wine that is produced in the far northern region of the Philippines, particularly Ilocos Region because the most important ingredient in making it is only available in this area - it is called Samak. The bitter basi gets better with age. To produce Basi, they put it in earthen jars and bury them in the ground for years.
When I was young, I remember the father's relatives bringing Basi coming from Ilocos Sur, so there was a time when we always have Basi at home and now that I am an adult, how I wish I can taste it too.