Time capsule in a bottle
Every glass bottle that we open is part of a tradition going back thousands of years. Glass is one of the oldest materials and closely intertwined with cultural history and cultural skills. Glass is used in art and architecture and to preserve and package the food we eat. Every glass bottle also represents a forward-thinking decision because glass protects the environment and preserves our resources.
7000 to 3000 B.C.
The story of glass does not even begin in Mesopotamia, where master craftsman discovered how to make glass in the third millennium BC. Glass occurs naturally. It forms when, at extremely high temperatures, quartz sand melts and then the molten mass cools down. "Solidified liquid", that's glass. Bolts of lightning bring high temperatures like this, but so do volcanic eruptions and meteorite impacts. This is how the glassy rocks fulgurite, obsidian and tektite are formed. Even in the Neolithic period (Early Stone Age), about 7000 BC, people were using glass as a tool. They recognised the outstanding properties of the naturally formed glassy rocks. For example, they used the sharp cutting edges of obsidian to make wedges and scrapers.
In about 1500 BC, the Egyptians produced the first hollow glass containers, which they used for ointments and oils. The oldest dated glass object can be seen in the State Collection of Egyptian Art in Munich: a dainty goblet made of pale blue glass.
© Picture: Staatliches Museum Ägyptischer Kunst
The library of the Assyrian king Ashurbanipal contains the first recorded recipe for making glass: "Take 60 parts sand, 180 parts ash from sea plants and five parts chalk." This formula, dating from the year 658 BC, has been unrivalled for two and a half thousand years. Quartz sand, potash and lime produce the natural, impermeable, malleable and strong raw material that is glass.
In about 100 BC, a technological revolution occurred at a glassmaker's hut on the Syrian coast: we do not know his name today, but the glassmaker invented the blowpipe. It consists of a tube about 1.2 to 1.6 m long, with a mouthpiece at one end. With the other end, the glassblower picks up the gob of molten glass, turns, swirls and rolls the cooling mass about and blows air into it. From then on, glassmakers were also able to make thin-walled glasses and all kinds of different shapes. 100 years later, luxurious glasses with extravagant decoration were already being produced in the Roman Empire.
From the 11th century on, Venice became the centre of glassmaking in the Western world. The glassmakers there, the "phioleri di Murano", achieved unimagined heights of craftsmanship, especially in the production and processing of pure crystal glass, and they developed the elegant Renaissance glass style within the Venetian glassmaking tradition.
Even though there were a few examples of Egyptians managing to make window glass, it was the discovery of the principle of crown glass that finally brought light into the castles and cathedrals of the Gothic period. The glass blowers pressed gobs of glass into flat discs and used lead to join together their central parts to form bigger areas.
It was in the French town of Saint Gobain that glassmakers first poured molten glass on to a table and rolled out the molten mass until it was the same thickness all over. This was ideal for making mirrors for the nobility to decorate their rococo palaces.
In 1867, Friedrich Siemens introduced a technical innovation which speeded up the industrialisation of glass production: the continuous bassin (tank) furnace. These tank furnaces still consist today of a melting end and a working end and are operated day and night without interruption. It was a milestone in the mechanical production of glass containers.
The American Michael J. Owens invented the fully automatic bottle-blowing machine, a masterpiece of engineering. It used the suck-and-blow process, i.e. the gob of glass is sucked into the metal mould and cut off automatically. 2,500 bottles an hour could be produced using this miracle machine.
In 1925, the engineers Ingle and Smith registered the patent for the IS machine. This produces hollow glass using the blow-and-blow technique, a production method that is still used to this day. A gob is pre-blown in a metal mould, then the pre-shaped gob is delivered into a second mould where blowing is completed.
In the second half of the 20th century, it was primarily the introduction of electronically controlled machines that increased the production volume for glass manufacturers. New processes for making lightweight glass help protect the environment and preserve our energy sources. Glass is an integral part of our lives. It is used in research, communications technology, architecture and solar systems. Glass is the ideal packaging material for drinks, food and cosmetics.