Flavoring and preserving the brews.
The list of plants added before or after the fermentation of beer such as flavorings and / or preservatives is almost endless. In antiquity, the beer was already the object of special care when one wanted to keep it long (adding antiseptic plants, increase the alcoholic content, sealed jars, etc..). Only the household beer spoiled after 1 or 2 days. A myth tells that beer could not be preserved before Pasteur's work. Chinese archaeologists have found 2000-year-old millet beer jars in a Han-era tomb, glazed, hermetically sealed and still filled! Ethnologists report that in some parts of the world traditional beers are kept for months in sealed jars. Similarly, bottled beer was found healthy in the holds of wrecked ships in the Baltic Sea in the early 19th century.
- Aniche G. N., Uwakwe G. U. 1990, Potential use of Garcinia kola as hop substitute in lager beer brewing, WJMB 6
- Behre Karl Ernst 1984, Zur Geschichte der Bierwürzen nach Fruchtfunden und schriftlichen Quellen, in Plants and ancient man : studies in palaeoethnobotany, W. van Zeist & W. Casparie (eds), A. A. Balkema, Rotterdam, 115:122
- Behre Karl Ernst 1999, The history of beer additives in Europe – a review, Vegetation History and Archaeobotany 8, 35:48
- Distribution maps of Myrica gale and Humulus lupulus for medieval Europe, based upon the plant remains discovered by the most recent archaeological published excavations. Complete and update Behre 1984.
- Birk Jürgen 1998, Tabaernomontanus und das Bier. Gesellschaft für die Geschichte und Bibliographie des Brauwesens, Jahrbuch 1998, 29:40
- Jabob Theodor Diether (1522-1590), botanist and physician, has described the hygienic virtues of beer in a chapter of his famous "New volkommentlich Kreuterbuch ...", and listed the 3 main reasons for its poor quality at that times.
- Buhner Stephen 1998, Sacred and Herbal Healing Beers. The Secrets of Ancient Fermentation.
- A must read. Knock down the bias that beer is only made from hops. Buhner lists all the plants used in beer making across ages and continents.
- Cordle Celia 2011, Out of the Hay and into the Hops. Hop cultivation in Wealden Kent and hop marketing in Southwark, 1744-2000, Studies in Regional and Local History Volume 9, University of Hertfordshire Press.
- DeLyser D. Y., Kasper W. J. 1994, Hopped Beer : The Case For Cultivation, Economic Botany 48(2)
- Doorman Gérard 1955, De Middeleuwse brouwerij en de gruit, The mediaeval brewery and the gruit, with a preface in English, Die Brauerei im Mittelalter und die Gruit, mit einem Vorwort in deutscher Sprache.M. Nijhoff ed., s' Gravenhage (La Haye), 105 p.
- An excise tax named Gruitrecht would have been born on the lower Meuse (Teisterbant) in the 14th century, on a territory where predominant among the brewers the use of a wild plant, the bastard myrtle (Myrica gale). A tax or tithe created to counter the trade of cultivated hops from Germanic countries and its use for brewing beer. The real nature of gruit, and most of all its real technical function, are still debated today.
- Edwardson John 1952, Hops - Their botany, history, production and utilization, Economic Botany 6(2)
- Freudenthal Gunter 2000, Auf den Spuren des Norddeutschen Hopfenanbaues. Gesellschaft für die Geschichte und Bibliographie des Brauwesens, Jahrbuch 1999/2000, 7:68
- Significant role of the grown hop in Middle-age for the Hanseatic beer trade and for the abbeys breweries.
- Hofsten Nils von 1960, Pors och andra humleersättningar och ölkkryddor I äldre tider [Bog Myrtle (Myrica gale) and Other Substitutes for Hops in Former Times], Acta Academiae Reglae Gustavi Adolphi XXXVI, Uppsala
- An in-depth study of the herbs and plants added to beer in Scandinavia, before the very recent domination of hops.
- Lasekan & al. 1999, Effect of Vernonia amygdalina (bitter leaf) extract on brewing qualities and amino acid profiles of stout drinks from sorghum and barley malts, Food Chemistry 6, 507:510.
- Lietz Peter 2004, Die Roh- und Zusatzstoffe in der Geschichte der Bierbereitung. Gesellschaft für die Geschichte und Bibliographie des Brauwesens, Jahrbuch 2004, 133:195
- A large inventory of starch sources and aromatic plants used in breweries during its history. Supplement Behre 1984.
- Parsons James 1940, Hops in Early California Agriculture, Agricultural History 14.
- Robinson D., Kristensen H. K., Boldsen I. 1992, Botanical analyses from Viborg Sonderso. A waterlogged urban site from the Viking period. Acta Archaeologica 62, 59:87.
- Simpson Michael & al. 1996, Past, present and future utilisation of Myrica gale (Myricaceae), Economic Botany 50(1).
- Verberg Susan, The Rise and Fall of Gruit, The Brewery History Society, Brewery History (2018) 174, 46-78.
- researchgate.net/...The_Rise_and_Fall_of_Gruit
- A comprehensive historical study of medieval gruit based on mainly Dutch sources. The 3 technical assumptions are well summarised: 1) gruit = aromatics 2) gruit = liquid or semi-solid malt concentrate 3) gruit = amylolytic ferment made with 4 plants ( laurel berries, bog myrtle, rosemary, laser-wort) and pine resin. See also her experiments to test hypothesis 2 => medievalmeadandbeer.