Certified Organic. Traditionally used as a bittering herb, for a mild bitterness and subtle, sage-like flavor. Use 1/4 to 1/2 oz. in the boil, or use in the secondary fermenter for a pleasing, aromatic effect. Yarrow has been widely used for millennia by cultures all over the world, and has been used as a brewer's ingredient for nearly as long. It has antiseptic and antibiotic properties effective in the treatment of colds, flu, and respiratory illnesses. It also aids in digestion, has mildly narcotic properties, and is a natural preservative.