Based loosely on the Guinness 1883 recipe in Ron Pattinson's guide to vintage beer, this recipe makes some modifications in an attempt to recreate the original cask-conditioned stout from 1821.

The Crisp Heritage Chevallier Ale Malt was the dominant barley variety in England from the 1820’s to 1920’s, since Ireland was under British rule in the 1820's, this is the most likely candidate for the base malt available on the market today.

Similarly, Crisp malt produce an amber malt that is used in dark milds and ESBs that is likely to be a good match for the reference to amber malt in Pattinson's Extra stout recipe, amber malt was a catch-all term for many crystal malts in the 19th century so using a period-correct crystal malt like Crisp malt's amber seems a better candidate to using another cara-crystal type malt. Finally, Crisp Black malt, developed in 1817 was the choice for colour additions at Guinness, as opposed to UK porter which still depended on brown malt for colour until 1821, the roasting temperature is broadly in line with Guinness's +/- a few degrees C. Some of the black malt is added after a cold steep so as not to extract too much harsh character, as the recommended dosage is 3%, and this is effectively double that.

Oxydized hop-flowers were used to brew with, they were left open in their packets for 2 weeks. The lack of cold supply chains from the growers in Kent and elsewhere would have meant that even fresh harvests would be partially oxidized on arrival to the brewery.

A deviation from the 1820's version is the water chemistry. In 1820 Guinness we're drawing water from the grand canal, which was fed from Lough Owel in Mullingar, the Lake has a Marlstone bottom, which would make the water rich in calcium carbonate, and therefore quite hard. Guinness later switched to softer water supplied from Wicklow and I've stuck to a balanced profile for this beer.

Finally, a dose of 10g of oak chips inoculated with Brettanomyces was added to the fermentation vessel during secondary fermentation. Brett. Claussenii was chosen as it shares 100% of it's DNA with Brett Anomalus, the strain originally extracted from British Stock ale and the most likely strain to have been found living in Irish barrels before steaming processes were implemented.