About 6 years ago, I was correlating pH buffering capacity with grain color for several "families" of grains - and the color side of things turned into a hot mess. After talking with a few maltsters and sending a number of European grain samples out for testing, some to an independent lab following ASBC protocols and some to a US maltster, this is what I think I learned:
-US maltsters simply measure SRM and report it as Lovibond.
-EBC has several methods for quantifying color based on the color range of a given grain. I wasn't able to find much detail, but I believe the spectrophotometric method is used for lighter grains and at least one comparison method is (was?) used for darker grains - and there's overlap on where they can be used.
-It was hard to find technical people at European maltsters to talk with, but I got a couple nuggets of info. It seems that when they report in degrees Lovibond, they try to get closer to true Lovibond than US maltsters by using equations like Lovibond = 0.375 x EBC + 0.56. Different maltsters used different variations of that equation, but they were all similar.
-All grains that tested under 90 SRM, a ~170 SRM UK crystal malt, and a German dehusked black malt were reasonably close to the equation Tested SRM = COA EBC / 1.97.
-All UK grains that tested above 500 SRM and a Belgian Special B were reasonably close to the equation Tested SRM = 0.375 x COA EBC + 0.56.
I only had 1-3 samples of each grain type tested (13 grain types total), so take my data with a grain of salt, but I think it's useful for highlighting the ambiguity of grain color reporting. If you unearth more info away from this thread, would you be willing to circle back and post a quick summary?
Thanks!
------------------------------
Joe Walts
Quality Manager and R&D Brewer
Karben4 Brewing
Madison WI
------------------------------