Before the use of hops as bittering, flavour and aroma agents of beer became widespread in the late Middle Ages, all sorts of weird and wonderful herbs were employed to achieve the same effects. These herbs are known as “gruit” and the beer resulting from their addition “gruitbeer”. Hops, as well as contributing to the sensory aspects of beer also play a very important preservative role: the resins and essential oils found in hops are powerfully antimicrobial, and are one of the reasons why even the most hopeless of home brewers’ batches are rarely contaminated to dangerous levels. (Home pickling or bean sprouting on the other hand are much higher-risk hobbies in terms of the potential to give yourself a dose of the squits). It is no coincidence that during the millennia prior to the universal adopting of hops, most of the herbs added to flavour beer also possessed antimicrobial properties.
Among the most commonly added gruit were rosemary, bog myrtle (sweet gale), coriander, caraway, nutmeg, cinnamon, ginger, juniper, milfoil, mugwort, thistle and yarrow. As well as the flavours and bitterness* the above herbs impart, many also contain psychoactive compounds. A spoonful of nutmeg will get you reasonably high, for example, not that I am advocating this practice, to which sailors in the old days used to resort when stocks of rum had run out. Mugwort (Artemesia vulgaris) is a cousin of wormwood (Artemesia absinthum) which is used in absinthe, a liqueur which fuelled much artistic creativity in the nineteenth century.
The name “mugwort” in itself is interesting. The received wisdom among brewers is that the plant was so named because of its association with ale: mugs, ale; ale, mugs — geddit? According to the Oxford English Dictionary, however, mugwort derives from the Old English mucgwyrt: mucg is derived from the Germanic word for moth, with wyrt similarly coming from a word meaning “root”. My faithful Encyclopaedia of Brewing by Christopher Boulton (2013, Wiley-Blackwell) begs to differ from the OED, claiming that the “mug” part of the word comes from the Old Norse word for marsh, an environment the plant tends to favour. As well as this, mugga in Old Norse means drizzle or mist. We still call humid and warm weather muggy. Perhaps Prof Boulton is correct?
*If you’re ever feeling brave, break open the stem of a thistle and sample a wee dram of the sap. You will never forget the peculiar bitterness which coats the mouth for hours!