Standard Reference Method (SRM)
We, as humans, are very visual. We use this sense to give us quick feedback on many aspects of life. Brewers only have one chance to set the first impression of a beer as it pours into our glass. Based on the style of the beer, the color is the first gauge for what we expect in a beer. Other factors like retention, lacing, and color of the foam play a big part also.
SRM is a scale for measuring the color intensity of a beer (it's more technical than this, but we will leave it there). SRM was adopted by the American Society of Brewing Chemists in 1951. There is another, older scale named degrees Lovibond (devised by Joseph Williams Lovibond) that the SRM scale has replaced.
The color chart and colors below are an approximation of the actual colors in the SRM scale. Two Beer Dudes tries to use these color descriptions or SRM number when rating beer. We hope that you will do the same so that everyone is on a level playing field while describing our beer experience. Enjoy!
Calculating Beer Color: The Morey Equation
This equation is typically used in beer software to approximate color. MCU = grainColor × grainWeightLBS / volumeGallons, then SRM = 1.4922 × (MCU ^ 0.68590). Good for color < 50 SRM.
Enter grain color, weight, and batch volume to calculate estimated SRM.
Beer Colors and SRM Value
| Color Swatch | SRM | Color |
|---|---|---|
| 2 | Pale Straw | |
| 3 | Straw | |
| 4 | Pale Gold | |
| 6 | Deep Gold | |
| 9 | Pale Amber | |
| 12 | Medium Amber | |
| 15 | Deep Amber | |
| 18 | Amber-Brown | |
| 20 | Brown | |
| 24 | Ruby Brown | |
| 30 | Deep Brown | |
| 40 | Black |
Beer Style SRM Color Ranges
| Style | SRM Range | Color Range |
|---|---|---|
| Witbier, Berliner Weisse | 2 - 4 | |
| Pilsner | 2 - 7 | |
| Belgian Strong Ale | 4 - 7 | |
| English Golden Ale | 4 - 8 | |
| Bavarian Weizen | 4 - 10 | |
| Maibock | 4 - 10 | |
| Oktoberfest | 4 - 12 | |
| Imperial Pale Ale | 5 - 11 | |
| Pale Ale | 5 - 14 | |
| Bière de Garde | 6 - 13 | |
| American Pale Ale | 6 - 14 | |
| Vienna Lager | 7 - 14 | |
| Märzen | 7 - 15 | |
| Bitter, ESB | 8 - 14 | |
| Dunkel Weizen | 9 - 13 | |
| Amber Ale | 11 - 18 | |
| English Brown Ale | 12 - 22 | |
| Bock | 15 - 30 | |
| Baltic Porter | 17 - 40 | |
| Porter | 20 - 40 | |
| Oatmeal Stout | 25 - 40 | |
| Foreign Stout | 30 - 65 | |
| Imperial Stout | 50 - 80 | |
| Source: Tasting Beer by Randy Mosher | ||
The color chart above tops out at 40 SRM (Black) because the human eye perceives anything past that as essentially opaque black. Laboratory spectrophotometer measurements can read much higher, which is why styles like Foreign Stout (up to 65 SRM) and Imperial Stout (up to 80 SRM) appear in the style ranges table.
Want to explore individual styles in detail? Browse our complete Beer Style Guide.
Frequently Asked Questions
What does SRM mean in beer?
SRM stands for Standard Reference Method. It is a scale adopted by the American Society of Brewing Chemists (ASBC) in 1951 to uniformly measure and communicate the color intensity of a beer.
What is the Morey Equation for brewing?
The Morey Equation is a mathematical formula commonly used in modern brewing software to approximate beer color based on malt bill color units. The formula is written as: SRM = 1.4922 * (MCU ^ 0.68590). It provides highly reliable approximations for beers measuring under 50 SRM.
What is the difference between SRM and Degrees Lovibond?
Degrees Lovibond (°L) is an older color measurement scale devised by Joseph Williams Lovibond in the 1860s that relied on matching beer samples to tinted glass slides. The SRM scale was introduced later to replace it with precise spectrophotometer laboratory measurements, though the values remain highly comparable for lighter colors.
How do you convert SRM to EBC (European Brewing Convention)?
The European Brewing Convention (EBC) scale is roughly double the SRM scale. To convert SRM to EBC, multiply the SRM value by 1.97 (EBC = SRM * 1.97). To convert from EBC to SRM, multiply by 0.508 (SRM = EBC * 0.508).