We talk a lot about puck prep and WDT and avoiding the dreaded clumps but it struck me that 9 bar of pressure is quite a lot. Physics isn’t my strongest subject but a quick Google revealed that 9 bar is equivalent to about 130lbs per square inch. Or a 60 kg person standing on your portafilter.
Given that most clumps dissipate with nothing more than a tap on the counter, this got me thinking about how clumps are able to survive 130lbs or pressure.
I get how an uneven bed, sloping puck or inconsistent grind could affect extraction and cause channeling but I don’t understand how clumps aren’t just smashed by that much force from the water.
Hoping someone who knows more about science can help explain!