How to check the quality of coffee?

Very often in the guise of a quality product sold outright abomination. Even coffee beans can be faked. They are made from a dough of barley, even clay. Then stalemate sprinkled with sugar and fried. And then mixed with real coffee. To distinguish a quality coffee-counterfeiting easy. Experts offer a simple way – a bit of ground coffee dissolved in cold water. Since most grains contain fat, the powder should remain on the surface. If the bottom of the precipitate formed, so in coffee contains impurities.