Using Brewing Herbs – An excerpt from The Homebrewer’s Garden by Joe Fisher and Dennis Fisher)
Brewing herbs have different characteristics, just as different hop varieties do. Most herbs traditionally associated with brewing are bitter. Others are more flavorful or aromatic. What you use an herb for and when you use it depends on the qualities of the herb and the kind of beer you wish to brew. Some herbs are multipurpose, though none approaches hops in overall utility. Beer without any hop character at all is an acquired taste. We usually add at least 1/2 ounce (14 g) of hops for a 5-gallon (19 L) batch of even our most herbal beers.
Bitter herbs include horehound, sage, dandelion, alecost, milk thistle, nettle, yarrow, gentian, clary sage, and betony. Add these at the beginning of the boil in place of or in addition to bittering hops. The bitterness that they add to beer will not necessarily resemble hop bitterness, and some may add medicinal or other unusual flavors. So its best to go easy at first.
Using Dry vs. Fresh Herbs
When following recipes, always use half as much dried herbs as fresh. Roots are the exception; they must always be dried before they are used in brewing.
Herbs that can be used for flavoring include juniper, spruce, rosemary, hyssop, borage, ginger, oregano, mints, bee balm, lemon balm, sweet woodruff, marjoram, elecampane, licorice, and thyme. Most of these are strong-flavored; unlike aromatic hops, they should be added near the beginning of the boil. The more delicate ones like borage and lemon balm can be added to the last 15 minutes of the boil. Some of the flavoring herbs also have powerful aromas; these do double duty when added to beer.
Rosemary, hyssop, lavender, chamomile, lemon balm, bee balm, elder flowers, and many other herbs can be used to provide aroma to beer. Just drop the dried herbs into the last few minutes of the boil as you would with aroma hops. Any of the aromatic herbs can also be used for dry hopping. Rosemary, a wonderfully aromatic herb, is a good choice for dry hopping. A few sprigs dropped into the carboy for a few days to a week before bottling will add a delicate, piney nose to the beer. Elderflower makes a good dry-hopping herb for mead making as well as beer brewing. Loose, dry herbs can be bagged in a hop bag for dry hopping so they won’t get all through the beer. Don’t worry about infecting your brew with dry herbs; the microorganisms that live on herbs can’t survive in the acidic , alcoholic environment of finished beer.