I use the term gruit to refer to any herbal blend used in an unhopped beer. Many traditional gruit recipes from Germany and the Low Countries were closely guarded secrets, since the right to make and sell gruit blends was a monopoly granted by the state. But somehow the idea has gotten around that there was a basic gruit recipe consisting of marsh rosemary (Ledum palustre), sweet gale (Myrica gale) and yarrow (Achillea millefolium). I was pleased to see that the beer historian Martyn Cornell debunks this in his book Amber Gold & Black: The History of Britain’s Great Beers, in the chapter “Herb and Flavoured Ales” (which is worth the price of the book). Since marsh rosemary tended to be used only when sweet gale couldn’t be obtained, he writes, it’s unlikely that they would’ve been used together.
He expanded on this a bit in a post to the hist-brewing listserv. Whatever the merits of that particular detail, however, I think it’s clear from the information that has come down to us that there was a great deal of variety in gruit blends… and that yarrow was often the keystone herb, no doubt because, as any homebrewer can easily demonstrate, it is one of the best hop-substitutes you’ll find: aromatic, bitter but not forbiddingly so (unlike sweet gale), and a reliable antiseptic. But I’m sure there were also gruits that were juniper-centric or gale-centric (among many other possibilities).
I’m open to other suggestions of how to describe beers made with flavoring and bittering agents other than hops. But to me, “herbal beer” isn’t sufficient, because it could easily just refer to a hopped beer with some creative adjuncts. Further, “herb” makes one think mainly of leaves and flowers, but tree bark, fir branches and all manner of roots and spices are exceedingly common in traditional beer recipes. So to me, the most expedient course is to continue using this newly revived word “gruit,” and just expand our notion of what it might include.