Chewing tobacco is a form of smokeless tobacco designed to be placed between the user’s cheek and gum to release flavor and nicotine. Unlike cigarettes, it is not burned, and the user absorbs the ingredients directly through the mouth lining. It is typically sold as loose leaves, plugs, or twists, which are coarsely cut or bundled pieces of cured tobacco. This product is distinct from moist snuff, which is finely ground tobacco, though both are categorized as smokeless tobacco.
The Core Ingredient: Cured Tobacco Leaf
The foundational component of chewing tobacco is the leaf from the tobacco plant, primarily the species Nicotiana tabacum. This common variety is favored for its cultivation ease and nicotine content, typically ranging from 1% to 3% of the dry leaf weight. Some manufacturers may incorporate the much more potent Nicotiana rustica, often called “wild tobacco,” which can contain nicotine levels up to nine times higher than N. tabacum.
Once harvested, the leaves must undergo a curing process to remove moisture, develop flavor, and alter the chemical composition. Air-curing is a common method for chewing tobacco, where the leaves are hung in well-ventilated barns to dry naturally over several weeks. This process reduces the sugar content in the leaf and is followed by a fermentation and aging period that develops the product’s characteristic taste and texture.
The final product’s strength is largely dictated by the nicotine naturally present in the leaf. During processing, the tobacco leaves are cut into strips of suitable size, sometimes with the stems removed. The processed tobacco is then ready to receive the various flavorings and humectants that define the final commercial product.
Intentional Additives: Flavorings and Texture Agents
Manufacturers intentionally blend the cured tobacco leaves with a range of additives to enhance palatability, maintain freshness, and mask the naturally harsh taste. Sweeteners are a prominent addition, often including substances like molasses, honey, corn syrup, or various forms of sugar. These sugars balance out the bitterness of the processed tobacco.
Flavorings are incorporated to make the product more appealing and commonly include mint, wintergreen, cherry, or licorice extracts. Licorice, in particular, is frequently used as a flavoring, a moisturizing agent, and a way to mellow the natural harshness of the nicotine. The use of these flavor additives is less regulated in smokeless products compared to cigarettes, making them a significant part of the final composition.
Humectants, such as propylene glycol or glycerol, are also added to the mixture to prevent the tobacco from drying out. These agents retain moisture, which helps to maintain the desired texture and chewability. The combination of these intentional additives can make up a significant portion of the product’s total weight, beyond the core tobacco leaf.
Hazardous Chemical Components and Byproducts
Beyond the tobacco and intentional additives, chewing tobacco contains numerous compounds unintentionally formed or absorbed during cultivation and processing. Tobacco-Specific Nitrosamines (TSNAs) are carcinogens formed from the nitrosation of natural tobacco alkaloids during curing and fermentation. These compounds include N-nitrosonornicotine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK).
The tobacco plant also absorbs heavy metals from the soil and fertilizers used during its growth cycle. Cadmium, lead, and arsenic are found in the final product and are classified as known or probable human carcinogens. These inorganic elements are absorbed through the mouth’s mucous membrane during use.
Polycyclic aromatic hydrocarbons (PAHs) are also present in smokeless tobacco products. The International Agency for Research on Cancer (IARC) has identified thousands of chemical agents in tobacco products, including other carcinogens like formaldehyde. The presence of these toxic components is a major factor in the health risks associated with using chewing tobacco.