At some point in the 1980s or ’90s, Olympia began manufacturing a 54mm group for its heat exchanger espresso machines, which otherwise have a 49mm group like the Cremina manual lever machines. One nice thing about this larger group is that it will have better temperature stability as compared to the smaller group. For example, Richard Penney’s 54mm NEWD portafilter weighs in at roughly 370 grams as compared to roughly 225 grams for the 49mm version.
The downside of having an Olympia Express “big group” espresso machines is that 54mm replacement parts are much harder to find than for 49mm machines. By special request, Richard was able to produce a very small batch—five units—of 54mm bottomless portafilters for Olympia “big group” machines. These large portafilters are almost as rare as hen’s teeth, and they will sell out fast. Get yours at the CoffeeBOS shop on Etsy while supplies last.