Short answers, pulled from the story.
The word butter derives from the Greek bouturon, meaning cow-cheese, and ancient Greeks and Romans considered it food fit only for barbarians. They used it primarily as medicine or an unguent for the skin rather than as a staple food. Pliny the Elder described it as the most delicate of foods among barbarous nations while Galen codified its use strictly as a medicinal agent.
The production of butter begins when cream is agitated to damage the protective membranes of fat globules, allowing the milk fats to conjoin into a single mass. This agitation separates the fat from the watery portion known as buttermilk, which is then drained away. The remaining butter grains are pressed and kneaded together to consolidate the butter into a solid mass.
Bog butter is a substance created by farmers burying firkins of butter in the acidic, antiseptic soil of peat bogs across northern Europe. This practice was most common between the 11th and 14th centuries and involved packing butter into barrels to preserve them for years. Archaeological finds from the National Museum of Ireland reveal these buried treasures as grayish, cheese-like substances that remain partially hardened and free from putrefaction.
The mechanization of butter production began in the late 1870s with the introduction of the centrifugal cream separator by Swedish engineer Carl Gustaf Patrik de Laval. The first butter factories appeared in the United States in the early 1860s, and by 1920, Otto Hunziker had published The Butter Industry to standardize practices internationally. In 1907, Swift and Company revolutionized distribution by packaging butter into small, rectangular sticks wrapped in waxed or foiled paper.
Cultured butter is fermented to develop a tangy flavor using bacteria that convert milk sugars into lactic acid, while sweet cream butter is made from fresh cream without fermentation. This process can take up to 72 hours, whereas sweet cream butter can be produced in just six hours. The United States and the United Kingdom dominate the market for sweet cream butter, while France and other European nations favor the cultured variety.
World production of butter made from cow milk reached six million tonnes in 2022, with the United States leading the market with 13% of the total. Butter is a semi-solid emulsion at room temperature composed of approximately 81% butterfat and is used as a spread, melted as a condiment, or employed as a fat in baking and sauce-making. The density of butter varies, and its natural color can range from deep yellow to nearly white depending on the animal's genetics and diet.