Is lovibond dead?

[Marshi]

Is the Lovibond measurement of color virtually defunct (SRM being the popular measurement system), or do people still use it?

On a similar note, what are the units that SRM measurements use? I see, for example, an amber ale might have an SRM of 7, but 7 what? What are the units used to measure that?

 

[ajdelange]

Is the Lovibond measurement of color virtually defunct (SRM being the popular measurement system), or do people still use it?

In the Lovibond system (invented by a brewer but used in many other industries) one visually compares the color of the beer to a series of tinted glasses. In the more modern methods the absorption spectrum of the beer is measured using a photometer or spectrophotometer. The modern methods are thus not subject to the vagaries of human interpretation, fatigue etc.

Most interesting to me in all this is that the Lovibond company is still in existence and still makes meters but these seem to use spectrophotometric techniques which eliminates the human factor. But why buy a spec from them when you could buy one from any of dozens of other manufacturers. The problem is that you don't know the mapping between the spectrum and the Lovibond values. If they were available you could compute Lovibond, SRM, EBC, tristim and augmented SRM from the same data set.

Yes, the Lovibond system is still in use but seems to be used mostly in rating the colors of congress mashes made from dark malt. I think this is passing as while one still sees, for example, 100 L crystal one sees these malts rated in EBC units more often these days.

On a similar note, what are the units that SRM measurements use? I see, for example, an amber ale might have an SRM of 7, but 7 what? What are the units used to measure that?

In the SRM method light of wavelength 430 nm is passed through 1 cm of beer and the log of the attenuation computed. IOW if 10 units of light intensity enter and 1 unit comes out the attenuation is 10 and the log of that is 1. The log of the attenuation is multiplied by 12.7 so the SRM of this beer is 12.7. Thus, strictly speaking, the units of SRM are dimensionless (based on a ratio) but people usually write 12.7 SRM and it's understood. BTW the factor 12.7 and the wavelength were chosen so that the SRM values would be close to Lovibond values.