What ensures a better cup of coffee, a spotless grinder or freshly ground coffee? I want to understand how I can make a better cup of coffee, so I recently purchased a Wilfa Grinder. However after reading the instruction manual it says that the 'blades' and bean cup cannot be submerged in water, only wiped clean. This means that you're never really going to get it spotlessly clean like you can with a manual grinder.

So my question is which of the following two scenarios provide a better cup of coffee:


Grinding from very good beans each time using the Wilfa Grinder, knowing that there will always be some old coffee residue on the blades.
Buying 250g of the same very good coffee, but having it ground before delivery?
Always grind fresh.

Considering that the roaster you buy the 250 gr pre-ground coffee also uses some grinder and at most wipes its burrs daily, I would go for the first option. The residual coffee could be easily removed by


wiping reachable parts first
then grinding a small amount of fresh coffee


before actually grinding for your cup.