Brewing in Ireland has an ancient history, which like different beer styles, has evolved over time. Historically Irish ales were fermented without hops and by the time the late 1700s came around porter breweries were in popular demand. By the 18th century most market towns in Ireland boasted at least one brewery with different regions producing different styles of beer. Ireland's hops were cultivated in the midlands and Carlow became particularly famous for having the best arable land in the country, land that to this day is still used for growing high quality malt. Old malt houses can still be seen all along the River Barrow and these would have serviced the breweries and distilleries of the country through the navigable river and canal system.