The Chemex coffeemaker was invented by Peter J. Schlumbohm, a doctor of Chemistry, in 1941. He applied his knowledge of laboratory apparatus and methods of filtration when designing the Chemex. The key to the Chemex method is the Chemex-Bonded filters which are 20 to 30 percent heavier than typical coffee filters and only extract the desirable parts of the coffee bean. The filter combines a very fine grain, required for holding back coffee sediment; with the right filtration speed (not too slow, not too fast) that promotes proper infusion. The filter is designed not to burst under the weight of the liquid during infusion and not to break when lifting out the grinds.