Keeping it Fizzy for Over a Century: the Crown Cap Closure


oxon-hill-cork

Figure 1.  Dessicated cork from Oxon Hill Manor (18PR175). Photo courtesy MAC Lab.

Baltimore has been home to a number of important inventions over the last several centuries; among them rubber surgical gloves, telephone poles and the Ouija board.  Perhaps few of these innovations have had as widespread of an influence as the crown cap closure.  Invented in 1890 and patented in 1892 by William Painter as a device for capping carbonated beverage bottles, crown caps became one of the world’s first successful disposable products.  In his patent application, Painter stated “… I have devised metallic sealing-caps embodying certain novel characteristics which render them highly effective and so inexpensive as to warrant throwing them away after a single use thereof..” (US Patent Office 1890).

Capping bottles and other containers to provide sanitary seals and to prevent evaporation and spoilage had long posed a challenge to manufacturers.  Corks, made from the bark of the cork oak (Quercus suber), were easily shaped into needed shapes and sizes, but were problematic in that they dried out and shrank.  This unfortunate characteristic is illustrated in Figure 1, which shows a misshapen and dried out cork that had once been used to stopper an eighteenth-century wine bottle.  Dry corks meant evaporation, spoilage and, for sodas and beer, a loss of the carbonation.  Early producers of carbonated beverages used several manufacturing techniques to circumvent leakage.  Some soda bottles were made with rounded bases so they could not stand upright, hence keeping corks moist and tightly-sealed.  Other manufacturers narrowed the interior neck of the bottle and stoppered it with a glass marble, held in place by pressure from the carbonated gas (Jones and Sullivan 1985).

bottle-crown-caps-250x250
Figure 2.  Modern crown cap tops.  http://3.imimg.com/data3/UB/UI/MY-5891322/bottle-crown-caps-250×250.jpg

The crown seal cap, fashioned from a thin, circular disk of tinned iron whose crimped rim gripped the glass lip, was the first truly successful solution to the challenge of carbonated beverage bottle closure.  Cork liners, sometimes supplemented with disks of paper, rubber or foil, prevented the liquid from coming into contact with the metal cap.  For many years that indispensable party accessory, the bottle opener (also invented by Painter), was needed to remove these caps, but more recently, twist-off crown caps have been developed.

The crown seal cap, which has changed very little in over a century, has become the universal standard for sealing bottle soft drinks and beer. Embellished with beverage names and company logos, these brightly colored caps have become collectible.  The website for the Crowncap Collectors Society International has a searchable database of over 43,000 caps (CCSI 2017).  Some rare caps are offered for sale for thousands of dollars and there are regular gatherings of collectors at “crownventions” held in Pennsylvania.  I doubt that William Painter, applying for his patent in 1890, could have foreseen the longevity and popularity of his invention!

patent-illustration

Figure 3.  Painter’s 1892 patent.  https://www.google.com/patents/US468258

References

CCSI  2017. Crowncap Collectors Society International.http://www.bottlecapclub.org/

Jones, Olive and Catherine Sullivan.  1985  The Parks Canada Glass Glossary for the Description of Containers, Tableware, Flat Glass, and Closures.  Studies in Archaeology, Architecture, and History.  Parks Canada, Ottawa.

US Patent Office.  1890  Bottle-sealing Device US 468258 A.  https://www.google.com/patents/US468258

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