Flor (Spanish an Portuguese for 'flower') is a variety of yeast found only in the region of Andalucía in southern Spain, and important in the manufacture of sherry. Normally in wine making it is essential to keep young wines away from exposure to air by sealing them in airtight barrels, to avoid infection by bacteria and yeasts that tend to spoil it. However, in the manufacture of sherries, the slightly porous oak barrels are deliberately filled only about five-sixths full with the young wine, leaving "the space of two fists" empty to allow the flor yeast to take form and the bung is not completely sealed.