Peanut butter is a food product usually consisting of roasted and ground peanuts, sometimes sweetened. It is commonly sold in grocery stores, but can be made at home. Many styles are available; the most popular are creamy (smooth) and crunchy, but honey-roasted or wholenut varieties can also be found. Creamy peanut butter is made by grinding all of the mixture very finely. The crunchier styles leave portions of the mixture with a coarser grind, resulting in larger pieces of peanut interspersed with the creamier fine ground mixture.
For people with nut allergies, the intense concentration of nuts in peanut butter can cause fatal anaphylactic shock. Peanut butter is often contaminated with aflatoxin.
In 1893, Dr. John Harvey Kellogg originated an early variety of peanut butter at the Battle Creek Sanitarium in Battle Creek, Michigan. Kellogg, along with his brother, Will Keith Kellogg, patented a process for making peanut butter, but it used steamed peanuts rather than roasted peanuts.