Gruit (alternately grut or gruyt) is an old-fashioned herb mixture used for bittering and flavoring beer, popular before the extensive use of hops. Gruit or grut ale may also refer to the beverage produced using gruit.
Gruit was a combination of herbs, commonly including sweet gale (Myrica gale), mugwort (Artemisia vulgaris), yarrow (Achillea millefolium), ground ivy (Glechoma hederacea), horehound (Marrubium vulgare), and heather (Calluna vulgaris). Gruit varied somewhat, each gruit producer including different herbs to produce unique flavors and effects. Other adjunct herbs included black henbane, juniper berries, ginger, caraway seed, aniseed, nutmeg, cinnamon, and even hops in variable proportions.
The 1990s microbrewery movement in the USA and Europe saw a renewed interest in unhopped beers and several have tried their hand at reviving ales brewed with gruits, or plants that once were used in it. Commercial examples include 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; Cervoise from Lancelot in Brittany (using a gruit containing heather flowers, spices and some hops); Artemis from Moonlight Brewing Company in Santa Rosa, California (using mugwort and wild bergamot, Monarda fistulosa, also known as bee balm or horsemint); Alaskan Winter Ale from Alaskan Brewing Company, Anchor Brewing Company's Our Special Ale, Haines Brewing Company's Spruce Tip Ale, Kodiak Island Brewing Company's Island Trails Spruce Tip Wheat Wine, and Baranof Island Brewing Company's Sitka Spruce Tip Ale, (all southeast Alaskan companies, except Anchor) using young Sitka spruce tips;  and Bog Water from Beau's All Natural Brewing Company in Vankleek Hill, Ontario, Canada (using Myrica gale, also known as bog myrtle). Brasserie Dupont in Wallonia, Belgium produces a gruit (Cervesia) for The Archeosite D'Aubechies an open air museum that interprets life from the Iron Age to the Roman Era. The recipe is based on archeological research. In the United States this beer is sold as Posca Rustica.
The exclusive use of gruit was gradually phased out in favor of the use of hops alone in a slow sweep across Europe occurring between the 11th century (in the south and east of the Holy Roman Empire) and the late 16th century (Great Britain). In 16th century Britain, a distinction was made between ale, which was unhopped, and beer, brought by Dutch merchants, which was hopped. Currently, however, ale usually refers to beer produced through a top-fermentation process, not unhopped beer.
The phasing out of gruit from brewing is linked to various factors. A possible political factor would be the general emancipation of princes (mainly German) from the political influence of the Roman Catholic Church in a movement that eventually was to lead to Martin Luther's protestations turning into a fully-fledged uprising of those princes against the authority of Rome, in what is known as the Reformation. Princes wanting to undermine the power of the Church therefore tended to promote brewing with hops rather than gruit, to try to cut off this revenue for the monastic orders who had a monopoly on it.
Some authors present the switch to hops as a Protestant crackdown on feisty Catholic tradition, and as a Puritan move to keep people from enjoying themselves with aphrodisiac and stimulating gruit ales by imposing the sedative effects of hops instead. However, the switch to hops started in Germany some four or five centuries before the Reformation. Its later gradual enforcement in the 15th and early 16th centuries can in part be traced through legislation drafted by political rulers before the Reformation started.
The use of hops also has the advantage, in perception or fact, that beer made with hops lasts longer and resists spoilage better than that made with gruit. This preservative effect is thought to have had a large impact on the early movement to switch over, although other plants commonly used in gruit mixes, for example sage, rosemary or bog myrtle, also have antiseptic properties likely to extend the shelf life of beer.
- Beer Blotter editors (November 12, 2010), "Alaskan Winter Ale is released", Seattle Post-Intelligencer
- James Roberts (June 4, 2014), "Spruced Up", Anchorage Press
- Oliver, Garrett; Colicchio, Tom (2011), "Pine, fir and spruce tips", The Oxford Companion to Beer, Oxford University Press, p. 655, ISBN 9780199912100
- Behre, Karl-Ernst (1999). "The history of beer additives in Europe — A review". Vegetation History and Archaeobotany 8: 35. doi:10.1007/BF02042841.