How can I measure the Colour of Beer?

The chemical reaction, known as the Maillard reaction, between amino acids and reducing sugars gives your beer the identifiable brown and amber hues. Not only is the colour important by effecting the consumer’s sensory anticipation of the beer’s taste, monitoring the colour will also help diagnose if there are any issues in the production of the beer.

To maintain the same high quality beers and ales, that create the same unique colour throughout production, batches need to be tested regularly to meet standards. A popular and reliable route for brewers it to use a spectrophotometer to test consistency.

A spectrophotometer uses a discrete wavelength of light to determine the concentration of certain components in a sample. The EBC (European Brewing Convention) states that a beer assay works by detecting how much of the yellow spectrum is absorbed at 430nm at a fixed path length of 10mm.

To take a reading, a sample of decarbonated beer/wort is added to a glass cuvette, this is placed in a spectrophotometer where a beam of light at a particular wavelength is passed through and the amount of light that is absorbed/transmitted by the substance is measured. The more light absorbed, the more of that compound there is in your sample. The beer sample must be measured against a blank sample to take a measurement.

Camlab sell a large range of spectrophotometers – you can look at an overview of these with our quick guide here. Any of the visible spectrum units can measure at 430nm however you may want to look at the UV-Visible range in order to test other aspects of your samples such as bitterness. You can check out our blog on how to test the bitterness of beer here.