Phenols are a category of aromatic, flavour-active compounds that are produced by certain species of yeasts as a survival mechanism, similar to how plants produce certain chemicals as defence mechanisms. In large-scale commercial breweries, these flavours are considered to be off-flavours. These off-flavours can be described as clove, herbal, peppery, bubblegum, banana, spicy, smoky, and at their worst, medicinal or “band-aid”-like. However, they are common in classic farmhou