Like hops, spices can be added at different stages of the brewing process: they may simmer in the mix throughout the boiling stage, or they may be added at the end or during storage. Regardless, their chief purpose is to lend taste and aroma to the beer.
Generally speaking, spices have a very powerful effect on the flavour of beer, so it is important to add them in very small quantities in relation to the other ingredients such as hops. Beer has traditionally always been flavoured with spices such as bog myrtle and juniper, which were also used as preservatives before hops came into use.
Among the most common beer spices are orange peel and coriander, which give witbier and other ales their characteristic fresh taste, but today microbrewers all over the world tend to be highly adventurous when it comes to giving beer a spicy character. In principle, it is only the imagination that imposes any limits. At the more extreme end of the spectrum, the Evil Twin brewery has put Spanish cured Iberico ham in its ‘Biscotti Break Special Edition’, while the American brewer Dogfish Head has added real moon dust from a meteorite to its Celest-Jewel-Ale. At Mikkeller, over the years we have used everything in our beers, from vanilla to weasel coffee (passed through the digestive system of a weasel), pepper, truffles, passion fruit, aniseed, cinnamon and smoked chipotle chili.