For beer drinkers, it is not just any brewery, but the font of all that is goodness and dark: the home of the dry stout Guinness.

Alas, St. James's Gate, the historic brewery in Dublin, will no longer be the primary source of Guinness under a capital investment plan announced today by its corporate parent, Diageo.

The company plans to spend about $1 billion to build a new brewery somewhere near Dublin and to renovate St. James's Gate, where Guinness began.

When the new brewery is completed, in 2013, it will vault over St. James to become the largest brewery in Ireland. "It will marry 21st century solutions to our 300 years of brewing tradition, craft, and heritage in what I believe will be a winning combination," Paul Walsh, Diageo's chief executive, said. Half the land on the St. James site will be sold, and it will produce Guinness only for the Irish and British markets.

So the St. James's brewery, overlooking the Liffey River, lives, but it will no longer be the beating global heart of the dark ale, celebrated in song and poetry and cited in James Joyce's Ulysses.

Guinness stout may still be the national drink of Ireland, but, as Patrick J. Sauer wrote here in March, twentysomething Irish drinkers increasingly seem to prefer vodka, lager, or cider over stout. Sales of Guinness in Ireland fell 7 percent last year.

St. James's Gate is also famous for being one of the greatest real estate deals in history. In 1759, Arthur Guinness leased the facility for a down payment of 100 pounds and a payment of 45 pounds per year for an astounding 9,000 years.

Keeping St. James's Gate open was important for reasons of image and history, company officials said. Another reason may be that the Guinness Storehouse on the site of the brewery is said to be the most popular tourist destination in Dublin.

The complimentary pint at the end of the tour probably helps.

Jeffrey Cane