Gruit (or sometimes grut) is an old fashioned herb mixture used for bittering and flavouring beer, before the extensive use of hops. Gruit or gruit ale may also refer to the beverage produced using gruit.
Gruit was a combination of herbs, some of the most common being mildly to moderately narcotic: sweet gale (Myrica gale), mugwort (Artemisia vulgaris), yarrow (Achillea millefolium), heather (Calluna vulgaris) and Marsh Labrador Tea (Rhododendron tomentosum, formerly known as Ledum palustre). Gruit varied somewhat, each gruit producer adding additional herbs to produce unique tastes, flavours, and effects. Other adjunct herbs were juniper berries, ginger, caraway seed, aniseed, nutmeg, and cinnamon or even hops in variable proportions; many of these ingredients may have psychotropic properties too. Some gruit ingredients are known now to have preservative qualities.
Some traditional types of unhopped beers such as sahti in Finland, which is spiced with juniper berries,and twigs, have survived the advent of hops, although gruit itself hasn't.
The 1990s microbreweries movement in the USA and Europe has seen a renewed interest for unhopped beers and quite a few have tried their hand at reviving ales brewed with gruits, or plants that once were used in it. Notorious current commercial example would be, to name but a few, Fraoch (using heather flowers, sweet gale and ginger) and Alba (using pine twigs and spruce buds) from Williams Brothers in Scotland, Myrica (using sweet gale) from O'Hanlons in England, Gageleer (also using sweet gale) from Proefbrouwerij in Belgium, and the Cervoise from Lancelot in Brittanny (using a gruit containing heather flowers, spices and some hops). (Full article...)