Author: Colin Byrne | Publishing Date: February 27 2024



One country's national holiday embraced by millions across the world claiming family and friendship ties to the emerald isle has grown and developed by adding numerous traditions to its ever-evolving legacy. St. Patrick’s Day first started in honor of Saint Patrick on the anniversary of his death, followers held an enormous feast for which Lenten food and alcohol restrictions were temporarily removed.

As the years passed, St. Patrick’s Day became less about the man and more about general Irish traditions, culture, cuisine and history. The first recorded St. Patrick’s Day parade in Canada was held in Montreal in the year 1824, and thanks to the thousands of Irish who emigrated to Canada to escape the potato famine in the 1840’s became even more participated in by all walks of life. Drinking dark style beers has become synonymous with this famous holiday with many favouring stouts and porters to celebrate the man who as folklore tells us "banished all snakes" from the land of rolling green hills.



The yeasts used to brew Ireland’s classic stout are genetically distinct from the ones used to make other beer styles. The Guinness brewery for example, has kept a record of the yeast strains it has used going back to 1903. A genetic analysis shows these are distinct from those used to brew other dark beers.

Diageo Ireland Unlimited investigated the evolution of yeasts used to brew Guinness over the years based on records kept by the Guinness brewery on the yeast strains used in its malty, bitter stout since 1903. Their team compared the genomes of 13strains ofS. cerevisiaethat are currently or have historically been used to brew Guinness, to 160 other strains, including six used in other Irish breweries.

Though the Guinness yeasts and the other Irish brewing yeasts belonged to the same lineage, they found that the former were genetically different enough that they belong to a previously unidentified sub population.



Dark malts used in the production of brewing wort have more of an altering affect on the ethanol fermentation process, phenol content, antioxidant capacity and the physiology of yeast cells than most brewers may initially think. An innovative element of research into this topic has shown a combination on the effect of beer wort colour and flavour altered by the use of dark specialty malts and specifics of fermentation and the characteristics of post-fermentation yeast biomass depending on the yeast strain used. Therefore, it is critical to choose the right strain for the malt forward beer style you are brewing.

Here at Le Labo, we have chosen two specific varieties to help you and your brewery develop the perfect malt forward dark beer for this festivity and all other occasions that present themselves.


Like the famous yeast used in the production of Guinness today, this Irish strain, although traditionally used in dry stout production, is versatile and performs flawlessly in high gravity worts. It produces just the optimum amount of esters in malty and roasted beer styles. It will also offer superb drink ability.


It wouldn't be a Celtic festival without paying homage to the Scottish brothers and sisters  across the Irish sea on Saint Patricks Day. There has always been a strong bond between these two nations and it shines through no more so than in the styles of beer they have developed throughout history. LSB3010 is particularly well suited for producing strong, dark, malty style beers. Its subtle ester profile, enhanced at higher temperatures, gives a nice balance to these richer and stronger beer styles. Its tolerance to high and low temperatures allows the production of a wide variety of beers and even excellent ciders.