French press
Coffee for use in a French press should be ground coarsely.  The use of a burr mill grinder gives a better grind than the whirling blade variety.  The ground coffee should be more coarse than that used for a drip brew coffee filter, and far coarser than that used for espresso. Anything other than a coarse grind will go through the press filter and into the coffee.  A French press can also be used instead of a tea infuser to brew loose tea.