Hops was introduced to brewing by continental monks from the 9th through 13th Centuries as a preservative and spice to beer. Previously, brewers used a gruit of twigs, flowers spices & herbs.

Ironically, the use of hops was resisted in England, which of course, later became fertile ground for pale ales & IPAs.

In the modern world, hops (flower of Humulus lupulus vine) have no other commercial use other than brewing.