The original Leibniz biscuit design is framed by 52 teeth.
Bahlsen introduced the Leibniz-Keks in Hanover in 1891 as a German rival to France’s Petit-Beurre, which had been created in 1886. Its rectangular butter-biscuit shape, ridged edge and central lettering became the brand’s visual signature.
The teeth are not a reference to Gottfried Wilhelm Leibniz’s mathematics. The biscuit was named after the Hanover-based philosopher and mathematician because he was one of the city’s most famous historical residents. The German word Keks also has an unusual history: Bahlsen originally used the English-inspired word “cakes,” but German customers pronounced it differently, helping turn Keks into a general German term for a biscuit.
The number can be confused with the biscuit’s lettering or with later Leibniz varieties, including chocolate-coated and wholemeal versions. The 52-tooth count refers specifically to the original Butterkeks design, not every product sold under the Leibniz name.