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GUINNESS Yeast Extract (GYE)

GYE PackagingGUINNESS Yeast Extract (GYE), a by-product of the fermentation process, was sold for over thirty years as a flavouring ingredient and as a soluble 'tonic' that was high in Vitamin B.

Yeast is a tiny living organism which grows and multiplies and is added to the brewing process to ferment the beer. Fermentation is a natural process. During fermentation, yeast feeds on the sugars left behind by the malt, converting these sugars to alcohol.

During fermentation, yeast multiplies about fifty times. Some of the fresh yeast is used again in subsequent brews. However, there is considerable surplus yeast produced, beyond the requirements for new fermentation.

In the early 20th century a large portion of this surplus yeast was dried for sale as animal feed. It was already known that yeast was a rich source of Vitamin B, which helps with nervous disorders and diseases such as Beri-beri.

At the time, the Brewery Chief Chemist, Dr. Millar, was experimenting with processing a yeast extract product that would not only be fit for human consumption but also palatable.

By 1920, Millar's experiments using pressed yeast were proving successful and market research for a soluble food extract was very favourable. It was decided to expand the plant's capacity and develop GYE. Millar's process was fine-tuned and developed over the following decades, incorporating new techniques such as extracting by centrifuge.

In 1934 a larger plant capable of producing a quarter ton of extract per day was built. GYE was officially launched in Ireland on 2nd November 1936. Unfortunately, due to patent restrictions in the UK, it could not be sold there.

By 1936, the GYE plant had expanded to a capacity of one ton a day and by 1950 the figure had risen to 12 tons per week. The Company even published a recipe book filled with a variety of suggestions for ways to use GYE in cooking.

GUINNESS Yeast Extract enjoyed popularity as an ingredient in soups, sauces and sandwiches and as a tasty 'tonic' until 1968.

An advertising leaflet and two packs of playing cards were among some of the items used in promoting the product.