New Breville and issues with crema

[Majster81]

Hi coffee experts. Here's my situation. I have been brewing espresso style coffee for years, but it's my first venture to high shelf machine and grinder as well as fresh coffee.
I got Breville 920 XL and Grinder Breville 820 BSS XL. Grind setting goes from 60-1 60 being corse and 1 fine. I grind my 4 days old 100% Arabica at 7 and dose around 18 gram of coffee into 2 shot standard basket.
My pull time is 35 seconds to produce just shy of 2 oz or around 55 ml. My pre infusion is set at 5 seconds with 70% of pump pressure.
Coffee starts flowing at 11 seconds mark including pre-infusion and is thick brown. My pressure is solid 9. After about 3-5 seconds pressure drops to 7 and stays there for rest of the brewing time
I initially get nice thick crema, but that sizzles out fast 20-30 seconds and it's gone.
Issue 1, pressure drops to 7 and does not stay at 9, perhaps channeling? since I do get mesh impressions on the puck
Issue 2, crema disappears fast.

If I grind a bit coreser, I get 2 full ounces in about 20-30 seconds, but my pressure doesn't reach 9, When I grind too fine, the pressure stays at 9, but I get 1.5 oz from 30 seconds pull.

Any tips to keep my crema alive longer and my pressure stable 9? It has to be 9 with 30 seconds pull and producing 60 ml of coffee. I am close but off by 10ml.

 

[shadow745]

First thing... how is the taste as that is what matters most? How is texture/mouth feel?

Second... if you get a lot of crema that dissipates quickly that is usually indicative of coffee that is a bit too fresh and needs to age a bit longer to mellow out.

The mesh pattern on the puck means you might be overdosing a bit and not allowing enough headspace. Try dosing 17 grams, keep the grind somewhat fine and see how that goes.

Do realize that a good extraction will start off thick/dark and slowly thin out/get lighter as the puck is saturated and gives up what good it has to offer.

 

[Majster81]

First thing... how is the taste as that is what matters most? How is texture/mouth feel?

Second... if you get a lot of crema that dissipates quickly that is usually indicative of coffee that is a bit too fresh and needs to age a bit longer to mellow out.

The mesh pattern on the puck means you might be overdosing a bit and not allowing enough headspace. Try dosing 17 grams, keep the grind somewhat fine and see how that goes.

Do realize that a good extraction will start off thick/dark and slowly thin out/get lighter as the puck is saturated and gives up what good it has to offer.

Taste is amazing. I have never tasted coffee this good. I mostly make Lattes and they taste like honey.

I am getting mixed results at keeping machine at 9 bars the whole time of extraction. It starts off nicely at 9 and quickly drops off at 7. I will try to under dose the basket a bit next time.