This article is from the Coffee and Caffeine FAQ, by Alex Lopez-Ortiz with numerous contributions by others.
Percolators violate most of the natural laws about brewing coffee.
o Don't overextract the oils and flavour. Percolators work by
taking coffee and reheating it and throwing it over the grounds
over and over and over again.
o Never reheat/boil coffee. This destroys the flavour. For best
flavour, boil the water, pass it over the grounds and retain the
heat. Don't reheat it.
Violating these rules may not sound like much, but these are about the
only rules there are. The effect of a percolator is to keep passing
boiling water/coffee over the grounds until there is no flavour left
and the flavour in the coffee is so dead that it's a worthless waste.
 
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