Guinness is produced using traditional brewing materials, 90,000 tons of Irish grown barley is used by the St. James's Gate brewery every year.
Malt - The majority of barley intake is germinated and dried to make malt, which is the main ingredient in Guinness Stout.
Roast - 10,000 tons of barley is roasted each year in roasting drums, to produce the unique color and flavor of Guinness.
Barley Flakes - 10,000 tons of barley is steamed and rolled every year.
Hops - Hops are used to give bitterness, aroma and preservative value to beer. Hops is an expensive ingredient, more valuable than tea, and the St. James's Gate Brewery uses over 600 tons each year mainly from the USA, Australia, England and Germany.
Milling - The malt is first milled into coarse flour, keeping the barley husk material as intact as possible.
Mashing - This involves mixing the milled grist (malt, flaked barley and roast barley) with hot water to change the starches in the malt into fermentable natural sugars, which will be separated in the next process.
Extraction - The porridge-like mash is transferred to a kieve which operates like a sieve, and the sugary liquid, is then filtered off to a third vessel - the Kettle. The spent grains which are left behind are removed automatically and sold for cattle feed.
Boiling - Once in the Kettle, the wort is boiled with hops for approximately 90 minutes. The hops holds the bitterness and aroma which is a characteristic of Guinness.
Cooling - After boiling and settling in the Kettle, the wort is pumped to the Fermentation and Beer Processing Plant (FBP).
Each brew produces the equivalent of 250,000 pints of beer. 4,000,000 pints made daily making the brewhouse the main user of energy from the power plant, using 40% of the stations capacity this is equivalent to the amount of light and heat it required for 4,000 homes.