In 1933, a lab worker trying to clean a beaker found a stubborn green film, and it wasn't just residue: It changed what kitchens and shipping could wrap.

A Dow Chemical Laboratory employee by the name of Ralph Wiley was attempting to wash laboratory glassware in 1933 when he came across a mysterious green slime that would just not wash off his beaker, no matter how hard he tried to scrub it. The discovery came from irritation rather than a regular “Eureka” moment. In fact, the green sliminess of the substance made it rather unpleasant to look at and handle, let alone consider for future use in cooking or marketing. However, it turned out to be polyvinylidene chloride, known better as Saran, according to Dow’s company history.

The very characteristics that caused annoyance in laboratory conditions soon came to inspire scientific interest, since they repelled moisture, adhered strongly to whatever surface they touched, and formed a protective shield virtually impenetrable to external air. They also indicated the possibility of using it in contexts where protection and sealing were more important considerations than convenience, even though these were the reasons why cleaning the film was extremely hard. According to Dow historical documents, the initial iteration of the material was not considered appropriate for home use right away due to its poor aesthetics and pungent smell. According to the company's own records, Saran had started out as an “ugly duckling”, and this awkward debut is particularly important since the creation of the invention could hardly be called an easy one.

The material became valuable because it blocked moisture and air unusually well

Scientists slowly began to develop its use in industry and the military before finally introducing it to ordinary homes, after they understood how valuable the peculiar coating could be in creating a protective shield. According to the historical chronology of Dow's research and discoveries, the new coating became useful in protecting machinery and other products during the period surrounding World War II, as the film offered effective protection against moisture, corrosion, and other environmental factors. It is worth noting that such a sequence is rarely considered when people think about how inventions become useful to consumers immediately after their development, and this was not the case with Saran.


According to the Britannica Encyclopedia, one property that made polyvinylidene chloride stand out was its high resistance to oxygen, water vapor, and chemical substances; consequently, this substance would be very useful in retaining the fresh state of its contents by keeping external elements away. These barrier effects were soon incorporated into food packaging as well. Reducing oxygen and moisture helped keep stored items fresher than most previous packaging did, but the real turning point in the development of plastic came once people recognized that the substance's industrial properties could also solve their domestic issues.

Saran changed quietly from a wartime material into a household routine

By the 1950s, Dow had refined the substance sufficiently to begin selling Saran Wrap in rolls suitable for home use, thus turning what was once an annoyance in the laboratory into perhaps the best-known item in the kitchen pantry in the twentieth century. Of course, the development of Saran Wrap was part of a broader trend in post-war society in which artificial substances produced by industrial chemistry increasingly entered our daily lives at home. But what makes the story of Saran Wrap so fascinating is just how unpromising its original form was: there was nothing about the original green film that would suggest any potential for commercial success.

Scientists began to question whether this quality might make it valuable, rather than how to strip away the persistent film. As the Science History Institute's digital collection explains, Saran would eventually come to be so strongly identified with American culture surrounding food preservation and packaging by the middle of the century that it became ingrained in everyday practice, to the point that most individuals stopped even considering it. This process of disappearing into habit was precisely what made the invention so historically fascinating. Saran Wrap became such a routine part of daily life that even the accidental discovery that had led to it would soon be forgotten.