Attenuation is the percentage of sugar that a yeast is expected to convert to alcohol, carbon dioxide and flavour compounds. Yeasts required to achieve a dry flavour profile (such as in a West Coast IPA) have a high attenuation, while yeasts required to leave more sugar unfermented (such as in a sweet dark beer) have a lower attenuation. The typical range for brewers’ yeasts is between 65 and 85 percent.
