Beer's Law - Dan A. Morey

Thank you for your series on beer color. I found the article by Ray Daniels on predicting beer color quite interesting and educational. I would also like to suggest a way to improve the formulas presented.

It has been well documented that beer color is not a linear scale. So why try to relate Malt Color Units to an estimated SRM by a linear equation? I propose a power equation would better approximate the color phenomenon.

What I did was: Assume MCU = SRM from 0 to 10.5, Daniel's equation holds in the range of 10.5 < MCU < 37, and Mosher's formula holds for MCU < 37. Then I plotted In (MCU) vs. In (SRM) and performed linear regression. This exercise resulted in a R^2 value of 0.97 (This is better than my linear fit with force zero intercept on the MCU vs. SRM graph - R^2 0.96). My resulting equation is:

SRM = 1.4922 [(MCU) ^ 0.6859] - for values of SRM < 50

Now there is a single equation that can be used to estimate the final color of beer. Also, in the age of calculators and computers, it is no more difficult to calculate than a linear equation.

I would like to close by saying it would be interesting to see the same technique applied to the raw data that Mosher and Daniels used to develop their equations. Again, I would like to thank them for their excellent work. Any takers?

Dan A. Morey
Lombard, IL