[10] When World War I broke out in 1914, employees at Guinness St. James Brewery were encouraged to join the British forces.

This was made possible due to a number of measures put in place by Guinness: soldiers' families were paid half wages, and jobs were guaranteed upon their return.

[13][14] During World War II, the demand for Guinness among the British was one of the main reasons why the UK lifted commerce restrictions imposed in 1941 to force Ireland into supporting the Allied Powers.

[20] This led to a scandal and criminal trial concerning the artificial inflation of the Guinness share price during the takeover bid engineered by the chairman, Ernest Saunders.

[22] In the 1980s, as the IRA's bombing campaign spread to London and the rest of Britain, Guinness considered scrapping the harp as its logo.

[23] Due to controversy over the merger,[citation needed] the company was maintained as a separate entity within Diageo and has retained the rights to the product and all associated trademarks of Guinness.

[26] The Irish Sunday Independent newspaper reported on 17 June 2007 that Diageo intended to close the historic St. James's Gate plant in Dublin and move to a greenfield site on the outskirts of the city.

[citation needed] Initially, Diageo dismissed talk of a move as a rumor, but as speculation mounted in the wake of the Sunday Independent article, the company confirmed it was undertaking a "significant review of its operations".

This review was part of the company's ongoing drive to reduce the environmental impact of brewing at the St. James's Gate plant.

[38][39][40][41] Diageo announced in February 2018 that the use of isinglass in draught Guinness was to be discontinued and an alternative clarification agent would be used instead, making the drink acceptable to vegans and vegetarians.

[43] High pressure of the dissolved gas is required to enable very small bubbles to be formed by forcing the draught beer through fine holes in a plate in the tap, which causes the characteristic "surge" (the widget in cans and bottles achieves the same effect).

[43] The perceived smoothness of draught Guinness is due to its low level of carbon dioxide and the creaminess of the head caused by the very fine bubbles that arise from the use of nitrogen and the dispensing method described above.

Advertising for alcoholic drinks that implies improved physical performance or enhanced personal qualities is now prohibited in Ireland.

[51] A 2003 study found that stouts such as Guinness could have a benefit of helping to reduce the deposit of harmful cholesterol on artery walls.

[86] Before the 1960s, when Guinness adopted a system of delivery using a nitrogen and carbon dioxide gas mixture, all beer leaving the brewery was cask-conditioned.

Casks newly delivered to many small pubs were often nearly unmanageably frothy, but cellar space and rapid turnover demanded that they be put into use before they could sit for long enough to settle down.

[87] With the move to nitrogen gas dispensing in the 1960s, it was felt important to keep the two-stage pour ritual in order to bring better consumer acceptance of the change.

[98] Guinness recommends that, to avoid the bitter taste of the nitrogen foam head, gulps should be taken from the glass rather than sipping the drink.

[105][106] A study published in 2012 revealed that the effect is due to the particular shape of the glass coupled with the small bubble size found in stout beers.

[110] Since the 1930s, in the face of falling sales, Guinness has had a long history of marketing campaigns, from television advertisements to beer mats and posters.

Guinness advertising paraphernalia, notably the pastiche booklets illustrated by Ronald Ferns, attract high prices on the collectable market.

[114] In 1983, a conscious marketing decision was made to turn Guinness into a "cult" beer in the UK, amidst declining sales.

The Guardian described the management of the brand: In the late 1980s and early 1990s, in the UK, there was a series of "darkly" humorous adverts, featuring actor Rutger Hauer, with the theme "Pure Genius", extolling its qualities in brewing and target market.

[118] From 1999 to 2006, the Michael Power advertising character was the cornerstone of a major marketing campaign to promote Guinness products in Africa.

The 1980s advertisement not only remained a popular iconic image in its own right; it also entered the Irish cultural memory through inspiring a well-known line in Christy Moore's song "Delirium Tremens" (1985).

[121] Guinness won the 2001 Clio Award as the Advertiser of the Year, citing the work of five separate ad agencies around the world.

As of 2004, Guinness ranked among the top three beer labels in Singapore and Malaysia, with a 20 per cent market share across Southeast Asia.

[126] This TV ad has been run every Christmas since its debut in December 2004 and features pictures of snow falling in places around Ireland finishing at St. James's Gate Brewery with the line: "Even at the home of the black stuff they dream of a white one".

About 40 percent of worldwide total Guinness volume is brewed and sold in Africa, with Foreign Extra Stout the most popular variant.

[143] The beer is brewed under licence internationally in several countries, including Nigeria,[144][145] the Bahamas, Canada,[146] Cameroon, Kenya, Uganda, South Korea, Namibia, and Indonesia.