When breakfast cereal was invented in the Nineteenth Century as a masturbation preventative (among other reasons), it proved difficult to physically chew. Some people would let their cereal rest in water or milk during the night to soften it. Eventually, milk became the most popular cereal softener. Why? Dan Lewis of Now I Know explores the likely reasons:
Why milk ended up beating out water was likely a combination of a few factors: taste, the perceived nutritional benefit from the high-calcium milk, and the relative lack of sogginess. In 2012, researchers at Pontificia University Católica in Chile tested cereal and milk versus cereal and water, and determined that the former was better unless you want a bowl of slop; as Gizmodo summarized, the cereal held up okay in milk but water “will turn your Corn Flakes to mush, fast.” And while cereal eaters of the late 1800s probably didn’t run variable-controlled and peer-reviewed experiments, their persona experiences probably led them to the same result. Plus, it kept them on a path to Heaven, apparently.