To make a coffee beverage in a coffee percolator, hot water is fed, at
relatively low pressure of about two atmospheres, into a sealed capsule
defined by a cup-shaped body housing a measure of ground coffee and
closed in fluidtight manner at an open end by a sealing wall connected
integrally to the cup-shaped body; the beverage being extracted from the
sealed capsule through hollow extraction needles, which have longitudinal
inlet slits of substantially 0.3 mm in width, and are inserted into the
sealed capsule through the sealing wall before the hot water is fed into
the sealed capsule, and so that the relative longitudinal slits extend
inside the sealed capsule by respective lengths at least equal to a third
of the depth of the relative cup-shaped body.