Beer Colour Calculator (SRM and EBC, Morey Equation)
Colour of a beer in SRM and EBC from the weight and colour of up to three malts and the batch volume, by Morey's equation.
Results
What this tool does
Adding up malt colour units, weight times colour divided by volume, works for very pale beers but overshoots badly for darker ones, because colour in a glass does not grow in a straight line. Daniel Morey's 1990s equation, SRM = 1.4922 × MCU^0.6859, bends that curve to fit measured beers and is the one most brewing software uses. Malts are sold in degrees Lovibond in America and in EBC in Europe; choose which one your labels use and the conversion is done for you. The result is a good guide but not a measurement: boil length, kettle caramelisation and the glass all change what you see.
Formula
MCU = Σ(lb × °L) ÷ gal · SRM = 1.4922 × MCU^0.6859 · EBC = SRM × 1.97
Variables
| Symbol | Meaning | Unit |
|---|---|---|
m1 | Malt 1: weight | kg |
c1 | Malt 1: colour | °L / EBC |
m2 | Malt 2: weight | kg |
c2 | Malt 2: colour | °L / EBC |
m3 | Malt 3: weight | kg |
c3 | Malt 3: colour | °L / EBC |
vl | Volume of finished beer | L |
cu | Malt colour given in | — |
SR | Beer colour (SRM) | SRM |
EB | Beer colour (EBC) | EBC |
CL | Roughly looks | — |
MC | Malt colour units (MCU) | — |
Worked example
- Malt 1: weight4.5 kg
- Malt 1: colour3 °L / EBC
- Malt 2: weight0.3 kg
- Malt 2: colour60 °L / EBC
- Malt 3: weight0 kg
- Malt 3: colour300 °L / EBC
- Volume of finished beer20 L
- Malt colour given in1
- Beer colour (SRM)8.7 SRM
- Beer colour (EBC)17.2 EBC
- Roughly looksAmber
- Malt colour units (MCU)13.1
Limitations
- The result is an estimate based only on the values you type. Real situations often include factors this calculator does not know about.
- The default values are typical reference figures, not measurements of your situation. Replace them with your own data whenever you have it.