Standard Reference Method, or SRM, is a method of measurement used to determine and define a beer’s color on a numeric scale using a photometer or spectrophotometer. The color of a beer is an important factor when judging a beer’s overall quality. Different beer styles are expected to fall into a specific color range, and the SRM is a way of measuring that. The lighter the color of a beer, the lower the corresponding SRM value will be, and, as expected, the darker the beer, the higher the SRM value will be. Beers range anywhere from 2 to in excess of 40 on the SRM scale. Below is a chart featuring the SRM value on the left with the approximate color and beer style example to the right.
West Coast Brewer SRM / Standard Reference Method Beer Color Scale
Lovibond is one of the methods used to measure the color of beer. Using the Lovibond method, a beer’s color is compared against colored glass slides to determine a numerical value for the beer. The more recently created and precise Standard Reference Method has for the most part replaced the Lovibond method.
The following chart shows approximate Lovibond numerical values with the corresponding color and is categorized by style of beer.
The color or colour of a beer is typically described using either the Standard Reference Method scale (SRM), Lovibond scale, or European Brewery Convention (EBC) scale, which reference a numerical value to define the color and shade, and in some cases clarity or turbidity of a beer. The higher the number, the darker the referenced color is.
A beer’s color is primarily composed from the pigments of the grains that make up its grain bill. The pigment of a grain will darken if it is toasted, caramelized, or roasted, and that will impart that color on the finished beer. In the case of an imperial stout, the roast of the malt is so dark that it makes the beer nearly black. It is important to remember that as the color of the grain darkens, the acidity typically increases. Beer can also gain color from adjuncts, such as fruits and sugars.