Chewing gum has a history stretching back thousands of years, with early forms indeed originating from trees. However, the gum found on store shelves today is largely a product of modern chemistry. While the concept of a chewable substance for various purposes has endured, the materials used have evolved from natural tree saps to sophisticated synthetic compounds.
The Original Tree Connection
For millennia, humans have chewed on natural substances derived from trees. The oldest known chewing gum, a piece of birch bark tar, dates back over 5,000 years and was found in Finland. This tar likely served purposes beyond simple enjoyment, potentially used for medicinal benefits.
In North America, Indigenous peoples chewed the resin from spruce trees, a practice later adopted by early American pioneers. This spruce gum was valued for its ability to moisten the mouth, clean teeth, and even suppress hunger or thirst during long journeys. The mastic tree, native to the Mediterranean, also provided a resin known as mastic gum, which ancient Greeks chewed to clean teeth, freshen breath, and aid digestion.
Perhaps the most significant tree in the history of chewing gum is the sapodilla tree, native to Mesoamerica. Its milky latex, known as chicle, was chewed by the ancient Maya and Aztecs for thousands of years. They recognized its elastic properties and used it to clean their teeth, freshen breath, and even as a filling for tooth cavities.
What Modern Gum is Made Of
The composition of modern chewing gum has shifted dramatically from these natural origins. Today, the primary component is a “gum base,” which is predominantly synthetic. This base provides the elastic, rubbery texture and is typically a blend of synthetic polymers, resins, and waxes.
Common synthetic polymers include polyisobutylene, polyvinyl acetate, and polyethylene, which contribute to the gum’s chewiness and elasticity. Polyvinyl acetate, for instance, can make up a significant portion of the gum base. These petroleum-derived compounds also help integrate other ingredients.
Beyond the gum base, modern chewing gum contains various other ingredients. These include sweeteners like sugar, corn syrup, or artificial alternatives such as aspartame and xylitol. Softeners, such as glycerin or vegetable oils, are added to maintain flexibility and prevent the gum from becoming brittle. Flavorings, colorings, and sometimes fillers like calcium carbonate or talc complete the mixture.
The Journey from Raw Material to Chew
The creation of chewing gum, whether historical or modern, involves transforming raw materials into a chewable form. For natural chicle, the process began with “chicleros” making zigzag cuts into the trunk of sapodilla trees, allowing the milky latex to drip into collection bags. This raw sap was then boiled until it thickened to the correct consistency, often over open fires.
Modern gum manufacturing starts with the gum base, typically delivered in solid blocks. This base is melted in large heated kettles to make it soft and pliable. Once molten, the gum base is transferred to industrial mixers.
In these mixers, other ingredients are gradually added. Softeners like glycerin, sweeteners (sugar, corn syrup, or artificial options), and flavorings are thoroughly blended into the warm gum base. This mixing process ensures a uniform distribution of all components. The blended gum mass is then fed into rollers, which flatten it into thin sheets. These sheets are then cut into individual sticks, pellets, or other shapes. Some gums may then undergo a coating process, where they are tumbled in rotating pans while liquid sugar or syrup is applied, creating a hard, glossy outer shell.