Color

Color starts with bookkeeping. Every malt’s weight times its color, divided by the volume of wort it is dissolved in, gives the malt color units. It is defined in pounds and gallons because every published fit was regressed against it in those units, so we convert your kilograms and liters at that one point and nowhere else.

From color units to a color

Malt color units are not SRM. Doubling the dark malt in a beer does not double how dark it looks, and turning the one into the other is a curve somebody fitted to real beers. We use Morey’s, which is the best behaved of the three across the whole range and the reason essentially every modern calculator defaults to it.

The other two are here because people ask for them. Daniels’ is a straight line regressed roughly over the middle of the range, and it cannot return less than 8.4 SRM, which makes it visibly wrong for a pale lager. Mosher’s has the same problem with a floor of 4.7. We clamp both back to Morey below their crossover rather than tell you a pilsner is amber.

Color is set in the kettle, so the volume in the calculation is the post-boil one. The curve runs backwards as well: when you aim a grain bill at a color, we search for the share of crystal and roasted malt whose color units come back out of the curve as the SRM you asked for.

The swatch

The swatch beside the number is an interpolation of the standard beer-color chart, and it is a picture rather than a measurement. Beer color is not one number: two beers at the same SRM can differ in hue, and none of this accounts for the glass you are drinking from. Read the swatch as “about this”, and the number as the thing to compare.

The beer these numbers come from

Reference pale ale — 20 L into the fermenter, a 60 minute boil.

Grist	Amount	Color
Crisp Maris Otter Pale Ale Malt	4.5 kg	2.8 °L
Thomas Fawcett Caramalt	0.35 kg	9.9 °L

Hops	Amount	Alpha	Addition
Magnum	15 g	13.5 %	60 min boil
Cascade	30 g	6.8 %	10 min boil
Citra	40 g	13 %	20 min stand at 80 °C

It comes out at
Original gravity	1.0507
Final gravity	1.0094
Alcohol	5.52 %
Bitterness	35.66 IBU
Color	5.14 SRM (10.12 EBC)
Into the fermenter	20 L

The numbers

Color (morey-1999)

5.14 SRM, from morey-1999.

SRM = 1.4922 × MCU^0.6859
⇒ Color = 5.14 SRM

Input	Value	Unit
Malt color units	6.06	MCU
Volume	22.11	L
Volume basis	post-boil	—

What it assumes:

• EBC = SRM × 1.97 = 10.1.

Sources:

• Approximating SRM Beer Color — Dan Morey, 1999
• The SRM beer-color reference chart, as reproduced by the BJCP color guide

Color (daniels-1996)

5.14 SRM, from daniels-1996.

SRM = 0.2 × MCU + 8.4
⇒ Color = 5.14 SRM

Input	Value	Unit
Malt color units	6.06	MCU
Volume	22.11	L
Volume basis	post-boil	—

What it assumes:

• EBC = SRM × 1.97 = 10.1.

Sources:

• Designing Great Beers — Ray Daniels, 1996
• Approximating SRM Beer Color — Dan Morey, 1999
• The SRM beer-color reference chart, as reproduced by the BJCP color guide

Color (mosher-1994)

5.14 SRM, from mosher-1994.

SRM = 0.3 × MCU + 4.7
⇒ Color = 5.14 SRM

Input	Value	Unit
Malt color units	6.06	MCU
Volume	22.11	L
Volume basis	post-boil	—

What it assumes:

• EBC = SRM × 1.97 = 10.1.

Sources:

• The Brewer’s Companion — Randy Mosher, 1994
• Approximating SRM Beer Color — Dan Morey, 1999
• The SRM beer-color reference chart, as reproduced by the BJCP color guide