Did you know beer is categorized into more than 100 different styles? This variety is one of the many reasons we love to homebrew! It also means beer can come in an array of colors due to to the malts and other ingredients used in the recipe.
To describe beer color, a numerical scale called the Standard Reference Method (SRM) was developed by the American Society of Brewing Chemists (ASBC) in 1950. SRM ranges from pale yellow (1 SRM) all the way up to black (40+ SRM) and is primarily affected by ingredients, particularly specialty malts, but process variables such as boil time can also affect color.
If you’ve read through a beer recipe, you may have seen a color listed in this range. Charts like the one above are helpful in identifying the color that corresponds to a given SRM and, thus, if a beer meets the style guidelines.
Brewers outside the United States frequently use a different scale named for the European Brewery Convention (EBC). To convert EBC to SRM, simply divide by 2, e.g. 20 EBC = 10 SRM. (The actual conversion factor is closer to 1.97, but dividing by 2 is simpler and good enough for most of us.)