Beer has been produced in Scotland for about 5,000 years. The Celtic tradition of using bittering herbs remained in Scotland longer than in the rest of Europe. Most breweries developed in the central Lowlands, which also contained the main centres of population. Edinburgh and Alloa in particular became noted centres for the export of beer around the world. By the end of the 20th century, small breweries had sprung up all over Scotland.
Despite a widespread belief that beers in Scotland used fewer hops than in England, all the available evidence shows that the Scots imported hops from around the world and used them extensively.
Brewing in Scotland goes back 5,000 years; it is suggested that ale could have been made from barley at Skara Brae and at other sites dated to the Neolithic. The ale would have been flavoured with meadowsweet in the manner of a kvass or gruit made by various North European tribes including the Celts and the Picts. The ancient Greek Pytheas remarked in 325 BC that the inhabitants of Caledonia were skilled in the art of brewing a potent beverage.
The use of bittering herbs such as heather, myrtle, and broom to flavour and preserve beer continued longer in remote parts of Scotland than in the rest of the UK. Thomas Pennant wrote in A Tour in Scotland (1769) that on the island of Islay "ale is frequently made of the young tops of heath, mixing two-thirds of that plant with one of malt, sometimes adding hops". Though, as in the rest of Britain, hops had replaced herbs in Scotland by the end of the 19th century, this Celtic tradition of using bittering herbs was revived in Brittany, France during 1990 by Brasserie Lancelot, and in Scotland by the Williams Brothers two years later.