Beer Color (SRM) Calculator

Beer color is measured using the SRM (Standard Reference Method) scale in the US and the EBC (European Brewery Convention) scale in Europe. Both measure the absorbance of light through beer to quantify color intensity.

Conversion between scales: EBC = SRM × 1.97 SRM = EBC / 1.97

Malt Color Unit (MCU) formula: MCU = (Weight of Malt in lbs × Color of Malt in °L) / Volume in gallons

Morey Equation (most accurate SRM estimate from MCU): SRM = 1.4922 × MCU^0.6859

MCU adds. SRM does not. This is the single most common mistake made with the Morey equation, and it is worth being explicit about. Work out the MCU of every grain, add those together, and convert the total once. If you instead convert each grain to SRM and add the results, you will overshoot, because the exponent 0.6859 is less than 1 and the curve flattens as malt piles up.

Worked example: A 5-gallon batch using:

• 8 lbs Pale Malt (2°L) → MCU contribution: (8 × 2) / 5 = 3.2
• 1 lb Crystal 60 (60°L) → MCU contribution: (1 × 60) / 5 = 12.0
• 0.5 lb Chocolate Malt (350°L) → MCU contribution: (0.5 × 350) / 5 = 35.0
• Total MCU = 50.2
• SRM = 1.4922 × 50.2^0.6859 ≈ 21.9 → Copper / brown

Convert those three grains separately and add the SRMs and you get 3.3 + 8.2 + 17.1 = 28.6, which is nearly a third too dark and would send you looking for a porter recipe instead of a brown ale.

SRM color reference guide:

Lovibond (°L): The unit used to measure grain color. Common grains range from 2°L (base malt) to 500°L (black patent malt). EBC grain color = °L × 1.97.