Bog Myrtle. Also known as “sweet gale,” and scientifically as Myrica Gale, bog myrtle grows, as its name might suggest, in marshlands in the northern latitudes. It was traditionally one of the primary elements of gruit, the flavoring and preservative blend of herbs used in brewing beer before the common use of hops, and it continues to be employed as an antiseptic, a sedative, an expectorant and an anti-itch medicine in herbal treatments.
Bog myrtle has played a substantial part in the history of brewing in Britain, Ireland and Europe, and into nearly modern times in Scandinavia, where it is known as “Pors.” It is nearly ubiquitous in mentions of gruit mixtures, and continues to be used by homebrewers and small traditional craft brewers in the areas in which it is found. It grows in swampy lowlands at the edges of lakes, ponds, and rivers in the boreal reaches of England, Scotland, and Ireland, northern Europe, nearly throughout Canada, and in the United States in areas approaching the forty-eighth parallel, as well as in Alaska. Henry David Thoreau mentioned it in his unfinished manuscript Wild Fruits in the 1850s.
In beer, bog myrtle imparts a somewhat astringent and resinous flavor and mouthfeel. It can be used as a partial hop substitute or as an herbal additive, either in the boil or in the fermenter, where interaction with alcohol can better integrate its overall effect.