Frequently Asked Questions
Q - I saw two color films side by side while judging, and noticed that they appeared to be quite different from one another. The old BJCP color film would give a very different color reference from the one given by the newer product -one was rating colors significantly darker than the others.
A - There is a major difference between the "old BJCP color film" and the "Beercolor" reference guide. David Davison's film guide is based on "a depth of at least 1" of beer while the Beercolor reference is based on one centimeter to about 1/2 inch of beer. Thus the Beercolor reference will be lighter in color.
Q- The colors are also different! Why?
A. - One could evaluate the "lightness" - "darkness" of beer with a white-to-gray-to-black scale and produce an accurate SRM value of the beer in study. However you are not really evaluating beer color. With so many colors or hues in each beer contributing to the overall lightness/darkness of a beer, it would be impossible to represent the actual color of that beer with a one dimensional scale. What is done to produce a comfortable guide is to sample many beers of these ranges of light and dark and add the most observed colors to these ranges. This provides a more realistic visual sample of beer color.
Q- Why make a guide calibrated at ½
A The Beercolor reference is calibrated at one centimeter to provide an extended range of lighter colors and to avoid diluting the beers of darker profiles. The greater the depth of the sample the darker it will appear to be. Darker beer samples of greater depths would appear very dark and black and color determination would not be possible. By using the ½ " sample, the range of beer color samples can be extended with out using diluted samples or guessing. Also - When calibrating beer samples a length of 1 centimeter is used so it is easy to transfer this information to this guide.
Q - Why is the guide as big as it is?
A After using several different types of guides, we decided that the most useful and accurate guide would not be small or contain patches of color. It was decided that a color strip could most accurately contain the representative colors found in beers of their respective SRM ranges. Extending the size/length of the guide would make it easier for the user to narrow down their selection of color.
Q -Why is your guide transparent?
A Most beer samples are not opaque as light passes through them. A transparent film best represents this condition. A major advantage of a transparent guide is to allow the background of the guide and the beer being evaluated to be the same. Many error causing problems with color evaluation are caused by background and bordering effects. By using a transparent film and following instructions the differences in backgrounds can be minimized. Also a transparent guide will become darker, or appear more color saturated, when placed on a light background as light is reflected through the guide and from the guide. This can be used to estimate samples of greater depth and with different backgrounds but is less accurate.
Q -Why does the BCL-BCR guide have the older EBC color values?
A- Actually the guide has both or either depending on your preference.
Review Early on the British Institute of Brewing (IOB) and the European Brewing Convention (EBC) use different methods for quantifying the color of beer and malt. Even after 1950 when the American Society of Brewing Chemists (ASBC) adopted the standard spetrophometric measurements of beer color using 1/2' samples and a light wavelength of 430 nm (ultrablue or ultrapowderblue), the other IOB and EBC were using different methods and a light wavelength of 530 nm (Green). These methods were not linearly related but generally the conversion formulas SRM = 0.377 EBC + 0.45 and EBC = 2.65 SRM 1.2 were used.
Since 1991 the EBC uses a 1 cm sample and a wavelength or 430. So now the ASBC SMR is measured for ½ at 430 nm with its corresponding absorbance multiplied by 10. While the EBC is measured for a 1cm sample at 430 nm but its absorbance is multiplied by 25. So todays conversion is much simpler -
SRM X 1.97 = EBC and EBC / 1.97 = SRM
However many maltsters and brewers still, especially in the US, use and reference to the older SRM-EBC conversion. So for convenience and to avoid some problems the older EBC values were used hard to break old habits. SRM is primarily seen in the US for beer and L° for grain. However since the lovibond measurements are more suibjected to human error more grain values are being presented with color references of the ASBC SRM. The default guide for the time being is the older EBC values.
However #2 The BCL BCR guides are also available with the newer, subsequent to 1991, values on them for those, especially in Great Britain and Europe who would prefer them.
Hopefully with time and more beer consumption a common system will come about.
Copyright © 2001 [Beer Color Laboratories]. All rights reserved.