Canadian Marcellus Gilmore Edson (February 7, 1849 – March 6, 1940) of Montreal, Quebec was the first to patent peanut butter, in 1884. Peanut flour already existed. His cooled product had “a consistency like that of butter, lard, or ointment” according to his patent application. He included the mixing of sugar into the paste so as to harden its consistency.
Edson, a chemist (pharmacist), developed the idea of peanut paste as a delicious and nutritious staple for people who could hardly chew on solid food, a not uncommon state back in those days. Peanut paste was initially sold for six cents per pound.
Edson was issued United States patent #306727 in 1884. The patent describes a process of milling roasted peanuts until the peanuts reached “a fluid or semi-fluid state”.