Kruunukorkit

Kruunukorkit, commonly known as "crown caps" in English, are metal screw-on caps used to seal glass bottles, particularly those containing beverages such as beer, soda, and wine. Originating in Finland, they were invented in 1915 by the Finnish engineer and inventor **Reino F. Leino**. The design was intended to provide a secure, reusable closure that could be easily opened and closed without specialized tools.

The original kruunukorkki was made of brass and featured a distinctive screw-threaded mechanism that allowed it to be tightly sealed onto the bottle neck. Over time, the material evolved to include aluminum, which became more common due to its lighter weight and cost-effectiveness. The term *kruunukorkki* itself translates to "crown cork" in English, though the design is not identical to the American crown cork, which was patented separately in 1892 by William Painter.

Kruunukorkit gained widespread popularity in Finland and later in other Nordic countries, becoming a standard for bottled beverages. Their use spread globally, particularly in regions where glass bottles were commonly reused. The cap’s design ensures a tight seal, preventing contamination and preserving the freshness of the contents. Additionally, the material is easily recyclable, contributing to sustainability efforts.

Today, kruunukorkit remain a recognizable symbol of Finnish innovation in packaging. They are still widely used in Finland and other countries, though modern alternatives like plastic and aluminum bottle caps have also become common. The original kruunukorkki design continues to be appreciated for its simplicity and effectiveness in sealing beverages.