Breville 990 / Sage Oracle Touch: tackling uneven flow and built-up grounds

Uneven flow before the two-year mark

I have used my Breville 990 for less than two years, and this is the first problem I’ve had. Over the last couple of days, the flow has been inconsistent: the same beans and grind fineness, but sometimes fast and sometimes slow. Here’s what I gathered from other people’s experiences.

How I tried to narrow it down

The troubleshooting guidance I gathered was to run extraction with an empty portafilter: an uneven or thin stream points to a water-path problem, while an even stream points towards grinding or tamping.

I was also advised not to add a manual tamp after the machine’s automatic tamp, including on other machines with tamping functions: the explanation was that it could disturb the puck and cause channelling.

What I did around the grinder

I switched off, unplugged it, let it cool and emptied the hopper. To remove the upper burr shown in photo three, I lifted its handle and turned it anticlockwise. It was extremely tight the first time. Rather than forcing it, I turned the grind setting to its coarsest position; then it came out easily for me.

I didn’t have a coffee vacuum. My tools were a very slightly damp towel, an air blower, cotton swabs and toothpicks. Water must be kept away throughout the process. I blew away grounds, used swabs to lift particles from the teeth, and gently picked off clumps stuck to the walls and burrs before clearing them with air. Around the rim I used the barely damp towel to lift larger clumps, trying not to touch the burrs.

If you regularly use dark-roasted beans, I think timely cleaning matters, and a coffee vacuum would be convenient. I wipe the steam-wand tip with a damp towel after every use, and it has never blocked for me.