The first sign of a antique coffee grinder, or mill, as enthusiasts call them, is the handle. Believe it or not, coffee is older than electricity. The first electric coffee grinder was created in 1938 but didn't become popular until the 1950's, which is when the hand powered coffee mills stopped being produced. Antique coffee grinders are always hand powered. Another sure sign of a antique coffee mill is the materials it's made out of. Antique mills are only made from glass, cast iron or wood. If you find a coffee mill made from plastic, that is a sure sign its post 1950 and it's a replica.
Serial numbers and brand awarness
When hunting for antique coffee mills, the brand can tell you what country it was from and give you an idea of what decade. Most coffee mill manufacturers printed their names right on the front of the coffee mill. If it's not on the front, then the brand should be stamped on the back. Another important detail to look at is the serial number; without looking up the serial number, telling the exact year of a antique coffee mill can be difficult. The serial number is usually located with the brand stamp. The MacMillan Index of Antique Coffee Mills is book that most mill collectors keep to reference serial numbers.
American coffee mill manufactures
Chances are if you are in the US coffee mill hunting you are more likely to come across American manufactures. The most popular manufactures that you are most likely to come across are
Charles Parker Co., Fray & Clark and Arcade King, who were all Connecticut based companies. A Pennsylvania based manufacturer called Logan & Strobridge is well known for making high quality cast iron mills dating all the way back to 1890. The Charles Parker Co. made mills from 1860 to 1950. In 1900 Charles Parker Co. started marking their mills with the initials C-P-C and then changed to Parker after 1920. Arcade King stopped making mills after 1910 but because their models were such high quality cast iron, these old mills are still rather common in antique shops.
European coffee mill manufacturers
Some of the most popular of the European manufacturers are; Kenrick from England, Spong from England, PeDe from Germany, Armin Trosser from Germany, DeVe from Holland, M-S-F from Spain and Elma from Spain. The Kenrick company from England manufactured the same model of cast iron mill from 1850 to 1948, these could easily all look the same if it wasn't for the serial number. However with the PeDe brand from Germany, all their mills are easily identifiable because they are all made from white glass and say "koffee" (that is German for coffee) on the front. The font PeDe used changed every couple of years making a mill from 1940 look very different from a mill made in 1920. DeVe in Holland is another company that is known for having art work painted on their glass mills, making them instantly recognizable.The style of art work will often be the sign of the decade in which the mill was made.