Guinness Yeast Extract, commonly known by its initials GYE, was an Irish

Ireland

Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

 savoury spread, made from yeast extract

Yeast extract

Yeast extract is the common name for various forms of processed yeast products made by extracting the cell contents ; they are used as food additives or flavourings, or as nutrients for bacterial culture media. They are often used to create savory flavors and umami taste sensations. Monosodium...

. It was a by-product

By-product

A by-product is a secondary product derived from a manufacturing process or chemical reaction. It is not the primary product or service being produced.A by-product can be useful and marketable or it can be considered waste....

 of the Guinness

Guinness

Guinness is a popular Irish dry stout that originated in the brewery of Arthur Guinness at St. James's Gate, Dublin. Guinness is directly descended from the porter style that originated in London in the early 18th century and is one of the most successful beer brands worldwide, brewed in almost...

 beer

Beer

Beer is the world's most widely consumed andprobably oldest alcoholic beverage; it is the third most popular drink overall, after water and tea. It is produced by the brewing and fermentation of sugars, mainly derived from malted cereal grains, most commonly malted barley and malted wheat...

 brewing

Brewing

Brewing is the production of beer through steeping a starch source in water and then fermenting with yeast. Brewing has taken place since around the 6th millennium BCE, and archeological evidence suggests that this technique was used in ancient Egypt...

 process and produced by Arthur Guinness Son & Co., Dublin. The product was launched in Ireland in 1936 and discontinued in in 1968.

In February 2007 Marmite

Marmite

Marmite is the name given to two similar food spreads: the original British version, first produced in the United Kingdom and later South Africa, and a version produced in New Zealand...

 produced a limited edition Guinness Marmite of 300,000 250g jars of their yeast extract with 30% Guinness yeast.
In addition to spreading on toast or bread, one or two level teaspoonfuls added to each quart

Quart

The quart is a unit of volume equal to a quarter of a gallon, two pints, or four cups. Since gallons of various sizes have historically been in use, quarts of various sizes have also existed; see gallon for further discussion. Three of these kinds of quarts remain in current use, all approximately...

 of soup

Soup

Soup is a generally warm food that is made by combining ingredients such as meat and vegetables with stock, juice, water, or another liquid. Hot soups are additionally characterized by boiling solid ingredients in liquids in a pot until the flavors are extracted, forming a broth.Traditionally,...

 enriched the flavour while enhancing the nutritional value.