Turpentine, often recognized by its distinct pine scent, is a fluid derived from the distillation of resin obtained from living trees, primarily pines. With a long history dating back to classical times, turpentine has been integral to many applications, serving as a solvent and a base for other materials. Its production process, while seemingly simple, involves transforming raw tree exudates into a versatile substance.
The Source: Pine Trees and Oleoresin Collection
Turpentine production begins with specific pine trees, which produce a sticky, aromatic substance known as oleoresin. This oleoresin, also called pine gum or crude turpentine, is the raw material for gum turpentine. To collect this resin, a process known as “tapping” or “turpentining” is employed, involving carefully made incisions into the tree’s bark.
Workers make V-shaped notches or cuts on the tree trunk, usually near the base, allowing the oleoresin to flow out. Containers, such as metal or clay cups, are then attached below these cuts to collect the flowing resin. The oleoresin gradually accumulates in these receptacles over several weeks. This method is sustainable, allowing resin collection without long-term harm to the tree.
Transforming Oleoresin: Gum Turpentine Production
Collected crude oleoresin undergoes distillation to separate its components, producing “gum turpentine.” The collected oleoresin, which is a mixture of volatile turpentine oil and non-volatile rosin, is heated in a piece of equipment called a still.
Steam distillation is a common technique. Oleoresin is heated with steam, causing volatile turpentine oils to vaporize at a lower temperature. These vapors rise, cool, and condense into liquid turpentine oil, which is collected separately from the solid rosin residue. The resulting turpentine oil is a clear, colorless liquid with a characteristic pine-like odor.
Alternative Industrial Methods
Beyond traditional gum turpentine, other industrial methods contribute to the supply. These processes utilize different raw materials and distinct production techniques. Two prominent alternative methods are the production of wood turpentine and sulfate turpentine.
Wood turpentine is obtained from the destructive distillation of pine wood, often utilizing materials like shredded pine stumps, roots, or logging waste. This process involves heating the wood in the absence of air, which breaks down the material and releases volatile compounds, including turpentine. The vapors are then condensed and collected, yielding wood turpentine. This method differs from gum turpentine production by using wood as the raw material rather than the resin from living trees.
Sulfate turpentine is another significant source, derived as a byproduct of the kraft (sulfate) pulping process in paper manufacturing. In this process, wood chips are cooked with chemicals to separate cellulose fibers for paper production. During this cooking, volatile organic compounds, including turpentine, are released and can be condensed from the digester gases. This method efficiently utilizes waste products from the paper industry, contributing significantly to the modern supply of turpentine.