So I am currently using a Quickmill Andreja (and I love it) along with a Macap grinder. I have had the setup since early June. The machine runs at 11.5 bars with a blank portafilter basket in, and came out of the box from Chris' that way. What is this doing to my shots and do I need to adjust it? The machine is not the new style with easy access for adjusting pressure, thus it will take a bit of work.


Thanks
Josh

Almost a decade ago when I got a Silvia she was running up over 12bar. Of course she had no gauge so didn't know this until I got a PF mounted gauge and then did the old washer OPV mod to bring pressure down to ~9.5bar with blank. Shot after difference was softer, fuller, smoother shot. Less harsh or metallic than with higher shot pressure.

Silvia is long since gone from our home but the same has held true various other machines now including our 3 coffeehouse Lineas which I run approx' 8.5 to 8.75bar shot running pressure.

Chances are, your 11.5 is actually 9 at the group head. Depending on where in the hydraulics the gauge capillary tube is located you can get 2 or 3 bars + at the gauge. The only way to make sure is to put a portafilter pressure gauge on it and check the pressure at group with flow but as long as the shots are good, there is no real need to mess with it. You could turn it down but keep in mind, that built in pressure gauge is more of a reference point than an absolute. The gauges tend to be quite inexpensive and inaccurate as well.

It is a relatively adjustment to make to see what changes you taste, if you have metric spanners. http://www.chriscoffee.com/faq#13 is a nice guide.

Dave is right on a couple counts. The brew head pressure can be significantly lower than the pressure indicated by the gauge and that the gauges in the machines are often not terribly accurate.

There have been threads about "why" machines ship with higher pressures than some might consider optimal, without any solid answer. I, personally, subscribe to the "less service calls when the machine chokes" theory.