The shelf-life of soft drinks is determined by the CO2 level, which decreases due to permeation through the packaging material. Therefore, most of the responsibility in the shelf-life extension of such products has to be attributed to the bottle material performances, such as the ability to maintain the internal CO2 through the shelf-life, that is, in other words, its barrier property to CO2.
From the beginning a successful drink depended on retaining the gas in the liquid and Thomas Henry a Manchester apothecary recommended that all bottles be very closely corked and sealed.
Traditionally, beverages have been packaged in glass containers capped with a natural or plastic cork to limit oxygen intake and preserve the organoleptic quality of the beverage.
The crown cork evolved from the natural cork stopper. Cork stoppers were effective closures but did not meet the need to be applied at speed. The automatic production of glass bottles was perfected in the USA in 1903. This provided bottles with uniform dimensions at the neck that could take a standard closure. William Painter had already filed US Patent 468226 in 1892 for the 'crown closure'. Painter's crown was lined with cork and characteristically had corrugations in the 'skirt'.
Crown cork are items made from tinned metal used to fit on top of beverage bottles to seal and lock the contents of the bottle from being easily opened and for preventing any item from escaping out or from entering into the bottle .The crown cork is made from tinned metals with the interior part in contact with the contents of the bottle being covered off by a plastic disc.
For many years virtually all carbonated soft drinks were packaged in glass bottles sealed with crown cork. This closure has short skirt with 21 flutes which are crimped onto locking position on the bottle head. The flutes are angled at 15° in order or maintain an efficient seal.
Crown cork: History and description
