Guinness Beer Was Once Brewed With Canal Water

Guinness is one of the world's most recognizable beers, brewed in Dublin for over 250 years. On New Year's Eve of 1759, in an act of monumental ambition, Arthur Guinness signed a lease on St. James's Gate Brewery for 9,000 years. The lease included a supply of water, and for much of the brewery's history, that water came from Ireland's Grand Canal.

Dublin's public water supply is centuries old, and in the 18th century, the main source was a reservoir known as the City Basin. As the city continued to grow, water from the newly built Grand Canal was used to supplement the city's water supply, becoming one of the main supplies of drinking water for Dublin's citizens until the 1860s. Being everyone's source of fresh water, this made the canal water the obvious choice for the brewery, with a good level of hardness for brewing dark ales like stout and porter, which includes Guinness. Per the Irish Family History Center, "The water used to make the stout was the moderately hard water from the Grand Canal."

This certainly wasn't unique to Guinness, either. As Irish Waterways History mentions, "Other breweries and distilleries were supplied with water by both the Royal and the Grand Canal." The Grand Canal, in particular, was built to carry water from at least 40 freshwater springs, via a waterway called the Milltown Feeder (also known as the Grand Supply). The Guinness brewery is still supplied with the same canal water today, but it's no longer used for brewing, now reserved only for washing.

Now a famously Irish staple, Guinness is as good as a cooking ingredient as it is to drink, and the Grand Canal played a huge role in its success story. Barges would be loaded with hundreds of barrels each, and carried across Ireland by the Grand Canal Company on the very same water used to brew the ale. Once the stout was delivered, the barges would return with shipments of malted barley to brew more. 

The brewery's canal water supply was first passed through filter beds to remove any detritus, specifically the filter beds at the Grand Canal's 5th Lock, but the brewers at Guinness were mindful of making their ale using water with consistent quality. The water from the canal, as well as the rivers, was variable, making it less than ideal. The company started drilling boreholes on its own site, to try and find a groundwater source, but there wasn't enough water to be found in Dublin's limestone bedrock. Eventually, Guinness started looking further afield.

Nowadays, in a break with tradition, the iconic ale is brewed with water piped straight from the Wicklow Mountains, helping to ensure that Guinness tastes best in its home city of Dublin. In contrast with the Grand Canal, the mountain aquifers provide water that's soft, with few dissolved minerals. Exactly where in the mountains the water comes from isn't publicized, but the Guinness family estate includes an area around a mountain lake, Lough Tay. The lake's north bank has been landscaped with white sand, and is now affectionately known as Guinness Lake for its resemblance to a full pint glass.