The Beer Colour Spectrum
Brewer's Blog #4
- November 23rd, 2016
- By Stephen Rich
The colour of a beer is inevitably the first thing that shapes your perception of that beer. For most people, colour tends to indicate richness and seasonality. Craft brewers say that a beer’s appearance can be deceiving, and that the aroma is a far more telling and powerful indicator of the beer’s characteristics. Although this is true, we are visual creatures by nature, and we will all in some way or another scrutinize the colour gleaming from the glass in hand and give in to its suggestive capabilities.
The Standard Reference Method and Beer Colour
Like many other craft beer characteristics, there is a calculated measurement for its colour, just as there is for alcohol content (ABV), bitterness (IBU), and carbonation level (volCO2). The most widely used measurement for beer colour in North America is SRM (Standard Reference Method). This measurement was officially adopted by the American Society of Brewing Chemists (ASBC) in 1951, and is scientifically determined by measuring the reduction in the intensity of a beam of blue light as it passes through 1 cm of beer. The beer’s SRM is the value of the amount of light lost, multiplied by 12.7 (for the European Standard EBC, the multiplier is 25). Therefore, the more light lost, the higher the SRM and the darker the beer. Another measurement of beer colour is Degrees Lovibond, which is more often applied to the colour of wort created by specific malts. It is a comparison of the colour of a substance to a series of amber to brown glass slides. The Lovi and SRM scales are very similar; in general, SRM is the more widely accepted form of measurement for beer.
The SRM scale ranges from 1 to 60, going from extremely pale to black. However, this scale cannot be accurately represented graphically because a picture of a colour does not account for transparency or density, which affects the amount of light lost to the beer. The scale can also be misleading, considering many black beers will be tested to SRM levels over 200. Don’t forget: beer is as much art as it is science.
How does malt affect a beer’s colour?
The vast majority of beer’s colour is derived from the malt used to brew it. Each malt will have its own Lovibond measurement associated with it to help brewers understand what effect on the beer’s appearance that specific ingredient will have. Generally, softer flavoured malts like Pilsner, Munich, and Wheat have low colour impact between 2 and 10 Lovi (pale to light gold). Caramelized malts can range anywhere from 20 to 80 Lovi and higher (golden to deep caramel and brown). Roasted malts generally have the largest impact on colour with Lovi measurements between 200 and 550 (dark brown to pitch black).
On all Cowbell craft beers, we list the SRM for that beer. This can help give you an indication of what to expect, but I always recommend tasting the beer to best understand it rather than examining the stats. Cheers!