Having briefly used a Bosco machine, I can attest to the wonderful espresso the machines allow you to make. I am wondering, though, why the Bosco style groups (not sure exactly who makes them) are being chosen to be the heart of the nicest of machines. You see these on the Kees Idrocompresso, recent model VA Athenas, and the upcoming Londinium I.

Given the same conditions (HX/group mounting location), what advantage do these groups have over say, a more typical Brasilia/CMA style commercial group?

Thanks

Chad

Hopefully someone with experience with Bosco as well as other common lever machines can chime in, but my guess would be build quality and appearance. Commercial lever group are very simple devices, and because of this, most are essentially the same with very small differences in spec such as travel, chamber dimensions, spring force, overall mass, etc. No doubt they are all extremely capable of great espresso, some may be almost indistinguishably better or more consistent or both. The other thing to consider is appearance and Bosco groups are the only group head that I know of that has a finished top with hidden bearings i.e. it doesn't need a cap to cover the exposed bearings and cam mechanism.
Compare this Bosco group from Londinium:

To this CMA group posted by Flint (Chert):

There's also the conti lever group which in my eyes doesnt need a cap either with the cool linkages. And the Faema Zodiac is still used on the spanish Quality Espresso machines (futurmat and others)

I reckon the Bosco group looks unremarkable next to a La San Marco, no cap either....

Appearances aside is there any reason why these groupheads have such a good reputation, perhaps better reliability or for taste reasons?

I got a chance to pull a shot on a Bosco yesterday and I can say for sure that the action was very smooth! It was also predictable in as much as it did not have a varying pull force up or down. I liked it!

Doug and Barb Garrott sell the Bosco machine. They wrote on their site that they could not get their Faema wall mount commercial lever to equal the shots of the Bosco. Now here of course we're talking about an entire machine with the group all fine tuned to each other. Bosco has been in business for over 50 years and is still run by the founder, from what I've heard. This must be as fine-tuned as it gets.

Is it not true that all commercial lever groups are, in fact, made by the same company?

(Bosco certainly do not make their own)

I would be very surprised if there is much difference between the various commercial spring lever groups, they are all at the top end of premium coffee equipment, I dont believe there is anything special about the group heads the Bosco uses.


(BTW the 'nicest machine' of all, the Izzo Pompeii uses a different group to the Bosco!!)

I am a fan of the San Marco style lever group which is very well designed and can be utilized with either a dipper or HX delivery system and gives great control of the brew water via an adjustable inlet valve on the back of the group. It is also a two spring design which helps provide a very constant even pressure.


This group is also utilized on the Izzo Pompeii and Brasilia Decurtis...



I have had several CMA (Astorias) and Rancilio and Faemas as well but have not found them to be as well designed, easily servicable, nor aesthetically pleasing as the San Marco. I have not yet had the pleasure of trying a Bosco/Fiorenzato style lever, but it appears to be a beautiful design and has a long history of funcionality and reliability.