The reason for so called "5 cent test " management of the puck dose is so that there is enough room left for the puck to expand inside the filter, with the group handle applied to the group, when it is saturated with water. The ideal volumetric size of the spent puck, is for it to have expanded enough to have "kissed" the shower, therefore resulting in an efficient brew (all other variables being good). That then allows for the most efficient exhaust of pressure and water from the puck at the end of the brew cycle - in machines that have a group valve - whether it be an electrovalve - solenoid - or a mechanical vavle - eg manual E61 type.
If the puck is underdosed OR the grinds are too fine OR if the beans are stale, the exhaust at the end of the brew cycle doesnt work properly leaving sloppy grinds to stick to the shower....
Hope that helps.
If the puck is underdosed OR the grinds are too fine OR if the beans are stale, the exhaust at the end of the brew cycle doesnt work properly leaving sloppy grinds to stick to the shower....
Hope that helps.

now we're being advised as to the best type of rice to use (don't use arborio) crikey!, seriously, I guess you could use Quinoa, poppy seed, pearl barley, split peas or any other grain that tickles your fancy.
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