Brew Pressure and PI Chamber?

[symbology]

Now that it looks like I have the minor issues resolved on my new Mini, I can get back to dialing it in.

With the stock OPV setting, the gauge would get up to around 10bar. On my Andreja I was happiest just between 8.5-9bar. So, I went ahead and dialed the Mini down to around the same 8.5-9Bar.

Something I am seeing is that the first signs of espresso or showing up at around 6-8 seconds now, where before (10Bar) it was more like 10-12 seconds. While I have not completely dialed it in after the change. it seems like I had more depth and body to the shots with it set to 10Bar. There may be something else that has changed (grind) that is causing this, but I have not messed with it enough to know. I was wondering if anyone else noticed anything like this when making brew pressure changes (with the PI Chamber)

The overall shot timing is still pretty close in the 30-35 second range.

-Allen

[Endo]

I have mine set to exactly 9 bar. I tried 8 to 10 bar, but it doesn't really make much difference.

The PI chamber will always give you about 6 seconds. Not sure how you got 10.

You will find the biggest change in taste will come from variation in your technique (assuming you have good fresh coffee). A small difference in dose (from 15g to 17g) can make a big difference. Also, how you grind, distrbute and tamp will determine a lot.

It doesn't take a lot to get a good shot with this machine.....but it takes a huge amount of practice to get consistant, excellent shots.

I hope your machine problems are over. You seem to have had your share

[symbology]

Yeah, it could have been a finer grind, though with a smaller dose.

I will see how things go.

- Beans are fresh 6-12 days out of roast (black cat - local pickup for me is easy)
- Distribution is the same
- Tamping is the same (nutating)

- Grind has varied
- Dose has varied
- Brew pressure has varied

Back before the change, a 30 second pull was a tad sour, 40 seconds was a bit bitter. 34-35 was really, really good. I have gotten some good shots since, but they don't seem to be as good. The body just does not seem the same. Maybe my taste buds are off. I will try again tomorrow and see how things go.

I am loving this machine (minus the minor issues). I really hated the Andreja and the large amount of water wasted on cooling flushes, and never really knowing if the temp was spot on, or not. With this machine, I do not have to worry about the brew temp. I can focus on all of the other aspects of the extraction.

Thanks for all the help/tips Endo.

[symbology]

I wonder if the hole in the water line could have caused the 10-12 second pre shot time. It was basically a hole in the line before the pump and could have caused (just enough) loss of pressure, especially initially. Remember, with the hole in the hose I could not run a tank filter as there was too much inlet line resistance. Yeah, this is probably why there was a difference.......

I

[chas]

That would do it. The PI chamber is just a piston with a strong spring behind it. While pressure is being expending in pushing the piston back, the puck pressure remains low. The lower the pressure, the longer it takes to completely push back the piston.