Ladies and gentlemen,

After spending countless hours reading this forum, I've upgraded my old Krups "espresso" machine into something more serious: a Bezzera BZ10 coupled with an Orphan Espresso Pharos.

I've been enjoying it tremendously, so thank you for all the advice I've gleaned here.

One little nagging thing though: the BZ10 came with the OPV set at close to 13 bar (about 12.8 bar, read with blind filter, I get the same figure at the beginning of 25-30s 1:2 espresso shots), instead of the Bezzera-standard 12 bar.

That's past the red zone on the nanometer, and the machine also makes a whistling noise at this high pressure.

I'm happy with the coffee but of course I wonder if I could get even better shots with a more conservative pressure.

A lower pressure would also allow for a coarser grind (I guess): the Pharos had to be set to grind so fine it requires quite some strength, and that's an issue for my wife. The (large) amount of crema I get from some blends was also a bit disconcerting at first.

But the real issue on my mind is the longevity of the pump.

Problem: it doesn't seem trivial at all to change the OPV setting, I couldn't find any instruction, so I would have to ship the machine back to where I purchased it.

So I'm wondering if I'm just splitting hairs, or whether I should really do something about it?

Thanks in advance for your advice!

PS: One thing I'm upset about and I hold this forum responsible for it: I'm not able to enjoy espresso at "regular" coffees anymore, they taste like crap!

Go to Bezzera's site, and download the BZ10 manual (it's the PDF labelled BZ10 9942047.03 gb ed02.13 rev00). The OPV is called a "suppression valve", you can change it by turning the part that has the waste water hose outwards.

Thanks a lot Jim. Should I be worried about voiding the warranty? (There's a warranty sticker that needs removing to open the body)

No idea if these things ever fail under warranty.

Even better , go to the same Bezzera site and ALSO download the accessories pdf. On page 60-61, you will see the "kit" to convert to a 9.0 bar suppression valve for your specific machine.

Thanks Eric, but I'm confused: why sell a kit if all it takes is turn a knob? Doesn't the kit also require to open the machine?

I downloaded the Accessory PDF, but pages 60-61 list a naked portafilter and couldn't find anything of interest in the catalog. (A naked portafilter is what I'm using, by the way)

jeff0984 wrote:Thanks a lot Jim. Should I be worried about voiding the warranty? (There's a warranty sticker that needs removing to open the body)

You wont be able to "remove" that sticker, you will have to break it to take the cover off.
That will void your warranty.
should you care about it ???..that depends on your attitude to warranties !

Thanks Eric, but I'm confused: why sell a kit if all it takes is turn a knob? Doesn't the kit also require to open the machine?

Both the Accessories Catalog and the BZ10 Parts pdf have been updated. I have the older accessories pdf and was referencing it. So, ignore what I said as Jim's response is most correct, assuming that the production date on your machine is after March 2013.

If you are concerned about the warranty, I would contact the place of purchase. As regards pump longevity, I would say that is a "toss up" because the pump flow rate and pressure are moving in opposite directions.

Thanks guys, I'll indeed contact the shop and ask what they think, they seemed knowledgeable. I guess it won't be long before I rip that sticker anyway... Thanks again!

Also keep in mind that a vibratory pump with a blind basket will read high because you have no flow. Most vibe pumps read 1.5-2 bars high with a blind basket so a 12.8 bar may be more like 9.8 when you are pulling a shot. Still a little high but not as high as you may believe. Cont worry about pump longevity. The pump operates at the same level regardless and your OPV simply vents the excess pressure back to the water reservoir to give you the desired pressure at the portafilter.

Thanks Dave.

The reading is over 12 bar also during brewing, especially at the beginning. It's actually very, very close to the reading with a blind filter.

I'm using 14g doses, which I believe is on the low end, targeting 28g of beverage in 25-30 sec, so I'm having to grind fine and tamp hard so that the water just doesn't flush through...

Or then there's something very wrong with my technique, which is highly possible too.