From the 18th century until the present day the true nature of gruit had been lost. There had been all kinds of speculations on what gruit had been. Popular belief stalled at gruit being a mixture of herbs. True, there had been varying collections of herbs in the gruit-houses (domus fermenti), but in the Latin sources on gruit those were hardly even mentioned. These herbs had no important role in beer while gruit had been indispensable; it was needed for brewing good beer. Later non-Latin sources from Arnhem and Cologne spoke of herbs and gruit as separate things.
Historian Hans Ebbing concluded concentrating wort must have been the main and most important aspect of making gruit in the course of his detailed study. Sadly his work (in Dutch) was never recognized by his colleagues and his research and conclusions never reached a wider audience.
In retrospect it is perhaps strange the solution discovered by Ebbing was never recognized. (Some came very close and knew gruit must have something to do with malt, brewing and fermentation, but they couldn’t figure out how). Not so strange perhaps because many more stories and books about beer are in fact largely folklore.
It has been some time now since I wrote ‘A note on the essence of gruit’ and getting the article published also took a long time. Meanwhile my research went on and I’m amazed at the amount of puzzle pieces that keep falling into place.
The Latin ‘fermentum’ makes absolutely no sense with a mixture of herbs, although it has been tried by some. Adding malt extract to beer will lead to an extra or extended fermentation and result in a better, thicker, stronger and more durable beer. With every little bit of extra alcohol, beer will get a bit more robust. Fermentation in itself forms a protective layer of CO2 around the beer as long as it continues. Explaining fermentum, and the workers in the domus fermenti, the fermentarii, is key, but there is much more.
The old gruit brewers had to operate on a very small scale and made only small volumes of beer at a time. Their scale was limited by the fact that the beer was hardly durable. The making of concentrated wort however, could very well be done on the larger scale of the gruit-house and resulted in a durable and compact paste. The paste was mixed with various herbs or not, according to local custom or demand of the particular brewer.
Because of Dordrecht sources we know the amount of gruit had to match the amount of malt that was used in the brew. We also know there must have been brewers that tried to get more gruit than ‘belonged’ to the size of their brew. This also hardly makes sense with herbs but does if one considers that extract will lead to a relative thicker and stronger beer.
Not only the common ‘fermentum’ is making sense with malt extract, also words as polenta, levarentur, frumentum, conservabimus and pigmentum, that are found in the old documents fall into place all of a sudden.
Polenta was translated by 16th century de Lobel as Naerbier or Graut, being concentrated wort. Graut or Grout was the equivalent of gruit, although in England the use of herbs seems to have been less or even absent. Levarentur speaks of the levitation or rising of the beer with fermentation. Frumentum is Latin for grain and conservabimus is about conserving the beer. Then there is ‘pigmentum’ that could relate to the circumstance that in concentrating wort coloring will occur as some form of caramelization, Maillard or other browning reaction. In lieu of modern types of colored malt this could very well have been a special asset.
At the very end of the 16th century there is still a (1593) Lehnbrief der Churfürst zu Cölln (Prince-elector of Cologne). He grants the gruit to Frau Walburg Gräfin zu Mörs, further downstream the river Rhine near Duisburg. Gruit is spelled in at least five different ways in this single document but is very clearly set apart from herbs: ‘einig grudt noch kraudt im bier zu thun’ is translated: ‘(to put) any gruit nor herbs in the beer’.
Early 19th century some Ale is still made with gruit spelled only slightly different; grout or graut. ‘A mystery hangs over the ingredient called grout, and the secret is said to be confined to one family in the district only’ (1808). The mystery is solved a few decades later; it could be found in the Latin text Bauhin’s Historia Plantarum (1651). This Latin text seems to lead back to de Lobels 1581 Kruydtboeck in Dutch. The real mystery is why the connection between grutt, gruta, gruit, gruut, grout and graut was never made before.
Historians often knew gruit was somehow connected with malt and brewing. Several pointed out some kind of brewing must have been going on at the gruithuis. There were invoices about a big kettle by the administrative chamber (Cameraars) of Deventer. There was Dieric, the kettle maker, who repaired the gruutkettle for seven shilling. ‘A porridge called graut, -a favorite dish of the Northmen-, for the cooking of which an unusually large kettle was provided’, reminds us of the graut porridge described by 16th century De Lobel that was also eaten in the Holland city of Delft.
Gruitbeer never became as durable as hopped beer, and making it was never as efficient and profitable. Reynolde Scot wrote about that in his magnificent book A Perfite platforme of a Hoppe Garden (1576): ‘And in the favour of the Hoppe thus much more I say that wheras you cannot make above eyght (8) or nyne (9) gallons of indifferent Ale out of one bushell of Mault, you may draw XVIII (18) or XX (20) gallons of very good Beere’. This much larger quantity of beer was also much more durable. Thus slowly of an era of unhopped beer came to an end.
The fabrication of gruit used to made sense with primitive brewing equipment, but today’s brewers still use malt extract sometimes for the very same reason it was used over a thousand years ago; in American Craft lingo, to get a ‘bigger’ beer.
All sources backing this article can be found in chronological order: History - Sources about beer - Gruit - Grutt - Gruijt - Grout - Graut
Graut is made like this.
One takes 6 or 8 pounds of crushed malt, boiling hot water 12 or 15 pounds, which mixed together and well stirred 6 times in a day, and with blanckets and straw very well covered soo long together in a clean barrel shall soak that it becomes thick as syrup. After that it shall be fired and boiled, and stirred very well to keep it from burning, till it is thick as porridge.