I was reading the third edition of the book put out by CAMRA and noticed that many of the EBC values given for beers seem ridiculous.
The first beer listed is a mild with an EBC of 100; which is like 50 SRM.
Guinness is listed as 203 EBC. But, there is a porter listed as 33 EBC, and another as 93 EBC. Most of the bitters are listed in the 30-ish range.
Everything else is spot on: gravities, abv%, hop utilization, etc.
Is there some type of old EBC scale that isn't used any more?
And, is there a better conversion to SRM than divide by 1.97?