A supertaster (a term coined by Dr. Linda Bartoshuk in 1991) is a person who reports an extremely bitter taste when exposed to a chemical called propylthiouracil (PROP). This reaction is caused by a taste receptor known as a PROP receptor taste bud (one of 25 known bitter taste receptors) that not all people possess. Supertasters are believed to experience the sense of taste to a greater degree and higher sensitivity than other individuals, especially in regards to bitter tastes. Individuals who don’t have the PROP receptor taste bud are known as nontasters.