Post Cereals first created the confection that would become Pop-Tarts in the early 1960s. The company had developed a process of enclosing dog food in foil to keep it fresh without refrigeration. They adapted the process to create a new breakfast food for the toaster to complement their popular cold cereals. Post announced their new product in 1963 to the press, giving them the name "Country Squares."
Because Post had revealed Country Squares before it was ready, Post's biggest competitor Kellogg was able to develop their own version in six months. Internally at Kellogg, the pastry was known as a "fruit scone." The company later changed the name to Pop-Tarts, intended to be a pun on the "pop art" craze of the time.
Kellogg test-marketed Pop-Tarts in Cleveland, where they sold out the initial test run of forty-five thousand cases. Kellogg quickly released Pop-Tarts nationwide, along with a stern warning to store managers to put them in the cake and cookie aisle, not the cereal aisle.
Post released their Country Squares in the same year, but sales lagged behind Pop-Tarts. It is widely believed that Country Squares failed because of their name. In the progressive culture of the time, with TV shows like The Beverly Hillbillies, the name Country Squares was associated with being backward and boring. Country Squares failed to take off, while Pop-Tarts became a sensation.
At first, there were only four flavors of Pop-Tarts: strawberry, blueberry, apple currant, and cinnamon. They were not frosted because it was believed that the frosting would melt in the toaster. However, they later discovered that frosting could survive the toaster and released the first frosted Pop-Tarts in 1967. Today there are a wide variety of Pop-Tart flavors, including chocolate, s'more, raspberry, and even French toast.
In 1971, a cartoon character named Milton the Toaster was introduced to promote Pop-Tarts. William Schallert from the Patty Duke Show voiced him. The campaign ended when a commercial showed a child hugging the toaster, leading to complaints that children might imitate the commercial and burn themselves.
In 1992, Pop-Tarts became the focus of more controversy when Thomas Nangle sued Kellogg for damages, after his Pop-Tarts got stuck and caught fire in his toaster. The case gained notoriety when humor columnist Dave Barry wrote a column about starting a fire in his own with Pop-Tarts.
In 1994, Texas A&M University professor Patrick Michaud performed an experiment proving that, when left in the toaster too long, strawberry Pop-Tarts could produce flames over a foot high . The discovery triggered a flurry of lawsuits. Since then, Pop-Tarts carry the warning: "Do not leave toasting appliances unattended due to possible risk of fire."
Pop-Tarts were introduced with fairly substantial marketing to the United Kingdom in the early 1990s, although they have failed to replicate their US success. The frosting initially had a tendency to melt off of the surface completely during heating and subsequently clog the toaster, a design error which suggests they may have been manufactured by a different company under licence. This is still a topic of debate.