METALS

Ancient boxes and cups, made from silver and gold, were much too valuable for common use. Other metals, stronger alloys, thinner gauges and coatings were eventually developed.

The process of tin plating was discovered in Bohemia in A.D. 1200 and cans of iron, coated with tin, were known in Bavaria as early as the 14th century. However, the plating process was a closely guarded secret until the 1600s. Thanks to the Duke of Saxony, who stole the technique, it progressed across Europe to France and the United Kingdom by the early 19th century. After William Underwood transferred the process to the United States via Boston, steel replaced iron, which improved both output and quality.

In 1764, London tobacconists began selling snuff in metal canisters, another type of today’s “rigid packaging.” But no one was willing to use metal for food since it was considered poisonous.

The safe preservation of foods in metal containers was finally realized in France in the early 1800s. In 1809, General Napoleon Bonaparte offered 12,000 francs to anyone who could preserve food for his army. Nicholas Appert, a Parisian chef and confectioner, found that food sealed in tin containers and sterilized by boiling could be preserved for long periods. A year later (1810), Peter Durand of Britain received a patent for tinplate after devising the sealed cylindrical can.

Since food was now safe within metal packaging, other products were made available in metal boxes. In the 1830s, cookies and matches were sold in tins and by 1866 the first printed metal boxes were made in the United States for cakes of Dr. Lyon’s tooth powder.

The first cans produced were soldered by hand, leaving a 1 1/2-inch hole in the top to force in the food. A patch was then soldered in place but a small air hole remained during the cooking process. Another small drop of solder then closed the air hole. At this rate, only 60 cans per day could be manufactured.

In 1868, interior enamels for cans were developed, but double seam closures using a sealing compound were not available until 1888.

Aluminum particles were first extracted from bauxite ore in 1825 at the high price of $545 per pound. When the development of better processes began in 1852, the prices steadily declined until the low price of $14 per pound in 1942. Although commercial foils entered the market in 1910, the first aluminum foil containers were designed in the early 1950s, while the aluminum can appeared in 1959.

After cans were invented and progressively improved, it was necessary to find a way to open them. Until 1866, a hammer and chisel was the only method. It was then that the keywind metal tear-strip was developed. Nine years later (1875), the can opener was invented. Further developments modernized the mechanism and added electricity, but the can opener has remained, for more than 100 years, the most efficient method of retrieving the contents. In the 1950s, the pop top/tear tab can lid appeared and now tear tapes that open and reseal are popular.

Collapsible, soft metal tubes, today known as “flexible packaging,” were first used for artist’s paints in 1841. Toothpaste was invented in the 1890s and started to appear in collapsible metal tubes. But food products really did not make use of this packaging form until the 1960s. Later, aluminum was changed to plastic for such food items as sandwich pastes, cake icings and pudding toppings.