DegL, SRM, and EBC: A Brief Look at Beer Colour Scales


The long, dark days of winter are past…which means that the heavy, dark beers of winter are slipping away too! This winter, I fell in love with rich, complex stouts and porters—especially coffee ones. Highlights include the Mocha Macchiato Stout from Old Bust Head, the Midvinterblot (an imperial porter) from Sigtuna Brygghus, and the Old North Mocha Porter from the Lake of Bays Brewing Company.

At Old Bust Head, trying the Mocha Macchiato Stout. I adored this beer.

At Old Bust Head, trying the Mocha Macchiato Stout. I adored this beer.

Now, scanning the shelves of the LCBO, we’re moving back towards pale and amber ales. Which makes sense: a heavy, oatmeal stout does seem kind of out of place in warmer weather. But considering all this also got me thinking about another aspect of beer:

Colour.

Black Creek's Ginger Beer (returning this June!). A VERY different look than the stout, eh?

Black Creek’s Ginger Beer (returning this June!). A VERY different look than the stout, eh?

Beer really appeals to all the senses: we all know about appreciating taste, mouthfeel, and aroma, but what about the way your beer looks in the glass? On the one hand, some beer judging competitions see focusing on appearance as an unacceptable bias. On the other—well, I think aesthetics are just another thing to appreciate.

In the 1860s, Victorians likely weren’t terribly fussed about the appearance of their beer. But in the 1880s, an English brewer named Joseph Williams Lovibond found himself growing increasingly preoccupied by the hue of his beers.

Different colours in beers largely come about as a result of the different propo rtions of malt roasts used. The longer you kiln your malt, the darker it will be. So, very dark beers have a higher proportion of these more darkly-roasted malts. Other factors can play a part too: more alkaline water or a higher-pH mash can extract more pigment from the grains, resulting in a darker wort, and filtered beer tends to look a little lighter, since the cloudiness has been removed.

So, colour can hint at what the beer might taste like. Lovibond began experimenting with different colour scales. At first, he tried paint chips, but that didn’t work terribly well. Eventually, he came up with a set of coloured glass slides. Using this “Tintometer,” he visually matched beer samples to the slides. Determining the closest match gave the beer’s colour value in degrees Lovibond. In 1895, Lovibond retired from brewing to focus exclusively on “colorimetry,” as he called it, and he established the Tintometer Ltd. Company the next year.

An advertisement for Lovibond's Tintometer.

An advertisement for Lovibond’s Tintometer.

Another view.

Another view.

You have to give the man credit: he definitely followed his passions.

Measuring beer by degrees Lovibond held sway for decades. Honestly, it’s still pretty useful today. But it is a qualitative measurement, fairly subjective. In the 1950, the American Society of Brewing Chemists came up with a more quantitative approach. They passed light at a wavelength of 430 nanometres through beer samples, and used spectrophotometers to measure how much light was absorbed/lost along the way. To make the numbers match more-or-less with the old Lovibond scale, the absorption was multiplied by 12.7. This is the Standard Reference Method, or SRM, and it’s still used today.

Simultaneously, European brewers came up with essentially the same idea, except that the level of light loss was multiplied by 25. Thus, values on the European Brewing Convention scale—EBC—are roughly double those of SRM.

(courtesy Wikipedia)

(courtesy Wikipedia)

If you’re just kicking back on the patio, do EBC or SRM units really matter all that much? Probably not, but I know that when I’m describing beers, I like to use a somewhat-consistent colour scale. When does straw change over into gold? At what point do we go from deep copper to light ruby? For general purposes, I’m still pretty indebted to Mr. Lovibond.

Clearly, there’s more to beer than meets the eye!

-Katie

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