Just out of curiousity. I've been reading before about different machines, and looks like the cheaper machines tend to have 15bar and the more commercial ones have 9bar of brew pressure.

So, question is, why not just settle ALL machines to be 9bar since that's what we use in the commercial setting anyway?

Just did a quick search, and it looks like much if not all of the machines that use 15 bar are also using pressurized portafilters. With pressurized portafilters, a coarser grind could be used but still pull something that tastes like espresso. The portafilter has a restricting orifice at the end that prevents the coffee from coming out too fast, and hence that more tightly constrains the overall extraction time and flavors you'd get. As a result, you can have a cheaper quality, non-commercial style grinder, or have your beans bulk ground, and still achieve acceptable results. The higher pressure, 15 bar, is likely to compensate for the fact that you are extracting larger pieces of coffee grounds and want to get as much flavor as possible. Summary: 15 bar machines are cheaper (~$150 for machine/grinder combo)

9 bar espresso machines come with unpressurized portafilters that are unrestricted in flow control - if you grind too coarse, the coffee will fly out. These machines require high quality burr grinders that can grind even and fine. They are also usually machines that come in the 53-58 mm portafilter size and that changes the equation significantly. The grinders that are suitable for commercial use rise significantly in price, especially as you try to get better and better extractions. Summary: 9 bar machines require nicer equipment, $500-10,000+ for machine/grinder combo

EstoCuppo wrote:Just out of curiousity. I've been reading before about different machines, and looks like the cheaper machines tend to have 15bar and the more commercial ones have 9bar of brew pressure.

So, question is, why not just settle ALL machines to be 9bar since that's what we use in the commercial setting anyway?

They are trying to make the cheap machines as cheap as possible....so no expansion valves or very very cheap ones....There comes a point with a machine where they are so crappily made, you are better of with a carafe or pour over.

I keep thinking about this too, but further research shows me otherwise, that the parts are cheap, so why just not add it in the first place. For example, for the Nuova Simoenlli Oscar 2, there is no OPV, but looking at elektros.it site, the OPV kit goes for 30 euros. I wouldn't think 30 euros is "that" expensive right?

They could have just added the OPV straight up and marked up the price to 50 euros.

The expansion valve costs the factory about 5 euro...even the best quality expansion valves might only cost around 8 euro. Honestly they will save even a few euro just to make a little more money, but deliver a vastly inferior machine. We have a saying in the UK "Spoil the ship for a hapeth of tar". The espresso machine manufacturers are past masters at this. They get away with it because mostly reviews are done by enthusiastic owners or "reviewers" who don't understand enough, don't care, or both.

EstoCuppo wrote: They could have just added the OPV straight up and marked up the price to 50 euros.

It's not just one part, there's gotta be the bypass tubing etc installed and tested etc.

Sure. But it seems like a pretty trivial task that wouldn't cost > $500usd.

Do correct me if I'm wrong?

In many cases 15bar is just a marketing trick for a cheap machine to look better. You can't be sure that it has opv or not from that. In reality, pressure will depend on the flow, about 15 bar is max for the pump with zero flow. Cheap plastic opv likely costs manufacturer less than 1$ anyway

EstoCuppo wrote:Do correct me if I'm wrong?

I don't know how they cost labour etc