What Is Turpentine Made From and How Is It Made?

Turpentine is made from the sticky resin that pine trees produce as a natural defense against insects and fungal infection. When that resin is collected and heated, it separates into two products: a volatile, aromatic liquid called turpentine (or “gum turpentine”) and a solid residue called rosin. There is also a second, industrially dominant form called sulfate turpentine, which is captured as a byproduct of the wood-pulping process rather than tapped from living trees. The chemistry, harvesting, and distillation behind these products are more varied than most people realize.

Why Pine Trees Make Resin in the First Place

Pine trees did not evolve their sticky, fragrant resin for the benefit of paint manufacturers. Oleoresin is a defense system. When a bark beetle bores into a conifer trunk, or when a fungal pathogen invades through a wound, the tree responds by producing and secreting a complex mixture of chemical compounds that accumulates at the injury site. This flood of resin physically flushes invaders out of the wound, kills them on contact, and then hardens to seal the damaged tissue like a natural bandage.¹ The defense is both pre-existing (constitutive resin stored in ducts throughout the wood and bark) and ramped up on demand when the tree detects an attack.²

The resin itself is not a single substance. It is a blend of dozens of terpene compounds, grouped loosely into a lightweight volatile fraction (monoterpenes and some sesquiterpenes) and a heavier non-volatile fraction (diterpenic acids). The lightweight fraction is what eventually becomes turpentine. The heavier fraction becomes rosin. In maritime pine, for example, more than 30 percent of the crude resin by weight is made up of this volatile turpentine fraction.³

Which Trees Are Used

Not every conifer produces resin in commercially useful quantities. The global turpentine industry has historically relied on a handful of pine species suited to warm or temperate climates where resin flows freely. Maritime pine (Pinus pinaster) dominates production in southern Europe, particularly in Spain, Portugal, and France. Slash pine and longleaf pine drove centuries of production in the American South. In Southeast Asia, Pinus merkusii (Merkus pine) is the main species tapped, while Pinus oocarpa is harvested in parts of Central America and tested for plantation use in tropical regions.⁴

The species matters because it shapes the chemistry of the final turpentine. Different pines produce oleoresin with different ratios of the key monoterpenes. Merkus pine resin, for instance, is notably rich in alpha-terpinolene (roughly a third of its turpentine fraction) alongside alpha-pinene and beta-pinene, while P. oocarpa resin is dominated by delta-3-carene with relatively modest pinene content.⁴ To a chemist buying turpentine for further processing, these differences are significant. Alpha-pinene and beta-pinene are the most commercially valued components, and a turpentine rich in them fetches a higher price than one dominated by other terpenes.

Larch trees also produce a historically important form of the product known as Venice turpentine, which has a thicker, balsam-like consistency compared to ordinary pine turpentine. Venice turpentine was once prized for medicinal ointments and fine art varnishes, though its use has diminished as synthetic alternatives have become cheaper.

How Resin Is Harvested from Living Trees

Traditional resin tapping looks a lot like tapping maple trees for syrup, though the technique and the product are quite different. A worker cuts a shallow wound in the bark, usually a V-shaped groove or a series of diagonal streaks, and attaches a small cup or gutter below the wound to catch the resin as it oozes out. This practice, sometimes called “tapping” or “scoring,” exploits the tree’s wound-response biology: the tree perceives damage and floods the area with oleoresin, which the worker collects periodically over the growing season.

The specifics of how you cut the bark make a measurable difference in yield. Research on maritime pine in Spain compared a traditional method (cutting long diagonal streaks into the bark) against a circular groove technique and found that the traditional approach produced about 1.4 times as much resin.⁵ Workers also apply chemical stimulant pastes to the freshly cut wound to keep the resin flowing longer. These pastes, based on compounds like ethephon (a plant growth regulator) or salicylic acid, can dramatically boost output. In one set of trials, stimulant pastes increased resin yield by up to six times compared to untreated wounds.⁵

More recent work has experimented with “micro-tapping,” which uses smaller, less invasive cuts. The resin yield per wound is lower, but the trees sustain less damage. In these micro-tapping trials, salicylic acid paste consistently stood out as the most effective stimulant.⁶ The broad trend in the industry is to optimize resin collection with better chemistry rather than more aggressive wounding, since a tree that stays healthy produces resin for decades.

Distilling Gum Turpentine from Raw Resin

Once collected, the raw oleoresin needs to be separated into its two commercial fractions: gum turpentine and rosin. The core method is steam distillation. The crude resin is loaded into a still and heated with steam or hot water. The volatile monoterpenes vaporize, rise through the still, pass through a condenser, and drip out as liquid turpentine. What remains in the still after the volatiles have been driven off is rosin, a brittle, amber-colored solid used in everything from violin bow rosin to adhesives and printing inks.

This general process has not changed fundamentally in centuries, though the hardware has improved. Modern facilities use stainless-steel stills, precise temperature controls, and vacuum distillation systems that allow the volatiles to be captured at lower temperatures, which reduces thermal degradation of the more delicate terpene compounds. Researchers have also tested microwave-assisted hydrodistillation as a way to speed up extraction and alter the composition of the recovered oil.³ But the basic idea remains: heat the resin, collect the vapor, condense it into turpentine.

Gum turpentine produced this way tends to have a relatively clean, well-defined terpene profile because it comes from fresh, uncontaminated resin. For artists and traditional users who care about purity and solvent behavior, gum turpentine from living-tree tapping is generally considered the premium product.

Sulfate Turpentine from Wood Pulp Mills

Most of the world’s turpentine today does not come from resin-tapping operations. It comes from the kraft pulping process, which is used to turn wood chips into paper pulp. When pine wood is cooked in a caustic chemical solution to dissolve the lignin that holds wood fibers together, the terpenes naturally present in the wood are released as vapors. These vapors are condensed and collected as crude sulfate turpentine, named after the sulfate (kraft) process that produces it.⁷

Crude sulfate turpentine is dirtier than gum turpentine. It contains sulfur compounds picked up from the kraft cooking chemicals, and these give it a harsh, unpleasant odor quite different from the sharp but not-unpleasant smell of gum turpentine. Its commercial value depends on removing those sulfur compounds through refining steps such as washing, distillation, and sometimes chemical treatment.⁷ Once refined, the terpene composition is similar enough to gum turpentine that it can be used for most of the same downstream chemistry, including as a feedstock for synthetic fragrances, flavoring agents, and industrial solvents.

The scale of sulfate turpentine production dwarfs traditional tapping. Any country with a large kraft pulping industry, especially the United States, Scandinavia, and Brazil, produces enormous quantities of it as a byproduct, essentially for free relative to the cost of running the pulp mill. This has made traditional resin tapping economically marginal in much of the developed world, though it persists in China, Indonesia, and parts of southern Europe where labor costs are lower and pine forests are managed specifically for resin.

A Nearly Forgotten Industry in the American South

Turpentine and its companion product rosin were once so important to shipbuilding that they were collectively called “naval stores,” a term dating to the era of wooden sailing ships. Tar and pitch (derived from heating pine wood in kilns) were used to waterproof hulls and caulk seams, while turpentine served as a solvent and preservative. The pine forests of the American South became a major global source of these products, and the naval stores industry supported much of the region’s economy for nearly 400 years.⁸

Nations fought wars over access to these coniferous products. England’s North American colonies were established partly to secure a domestic supply of naval stores, breaking dependence on Baltic sources controlled by Sweden and Russia. The longleaf pine forests of the Carolinas, Georgia, and Florida became the center of an industry that at its peak employed tens of thousands of workers, many of them enslaved people and, later, low-wage laborers working under brutal conditions in remote pine woods. Even after the age of sail ended and petrochemicals began to dominate, international demand for turpentine and rosin continued well into the twentieth century.⁸ The decline of the traditional naval stores industry in the South was gradual, driven by forest depletion, labor changes, and the rise of sulfate turpentine from pulp mills.

What Turpentine Actually Contains

When people say “turpentine,” they are referring to a mixture, not a single chemical. The dominant molecules are alpha-pinene and beta-pinene, two closely related bicyclic monoterpenes. In most commercial turpentines, these two compounds together make up the majority of the liquid. The rest is a changing cast of minor players depending on the pine species, the growing conditions, and the method of production. Delta-3-carene, limonene, beta-phellandrene, and alpha-terpinolene are common supporting characters.

Alpha-pinene is the molecule most responsible for the characteristic sharp, resinous smell. It is also the most commercially useful component, serving as a starting material for synthetic camphor, pine oil disinfectants, and a range of fragrance compounds. Beta-pinene is the main feedstock for producing myrcene, which in turn is converted into linalool and geraniol, two of the fragrance industry’s most widely used aroma chemicals. The fact that these molecules come from a renewable, tree-based source makes turpentine-derived chemicals an increasingly appealing alternative to petroleum-based feedstocks in the fragrance and flavor sectors.

Quality standards for turpentine have long focused on ensuring that what is sold as turpentine actually meets a defined terpene composition. ASTM International maintains standard test methods for sampling and testing turpentine, covering procedures for evaluating pinene content and other characteristics.⁹ Internationally, the process of standardizing turpentine has been surprisingly contentious. When the ISO tried to establish a universal standard for turpentine composition, France was accused of manipulating scientific definitions to protect its domestic maritime pine industry.¹⁰ The underlying issue was that different pine species produce turpentines with noticeably different compositions, and any standard that defined turpentine too narrowly would effectively exclude the product of another country’s forests.

Safety and Health Risks

Turpentine has a long folk-medicine history, but by modern toxicological standards it is not something you want to inhale heavily or ingest. The primary concern for most people today is inhalation exposure during painting or varnishing. Controlled exposure studies in men found that breathing turpentine vapors caused discomfort in the throat and airways, with a measurable increase in airway resistance after the exposure period ended.¹¹ The subjects in those experiments reported more throat and airway irritation from turpentine than from exposure to its individual purified components at comparable concentrations, suggesting that the full mixture is harsher than any one compound alone.

Longer-term occupational exposure raises more serious concerns. A study of art students regularly exposed to turpentine while painting found statistically significant increases in markers of genotoxicity and cytotoxicity in their cells compared to unexposed controls.¹² Genotoxicity means damage to genetic material, and while a single study of painters does not prove that turpentine causes cancer, it is the kind of evidence that pushes occupational health guidelines toward recommending good ventilation and limiting exposure time. Most professional painters and conservators now use turpentine substitutes (low-odor mineral spirits or citrus-based solvents) for routine studio work, reserving real turpentine for specific applications where its solvent properties are hard to replicate.

Ingestion is a separate and more immediate hazard. Swallowing turpentine, even in small amounts, can cause burning of the mouth and throat, nausea, and damage to the kidneys and central nervous system. Despite this, folk remedies involving turpentine consumption persisted into the twentieth century and occasionally resurface on social media. Poison control centers advise against any internal use.

Historical Medicinal Uses

Before synthetic pharmaceuticals, turpentine was a common ingredient in the apothecary’s toolkit. Venice turpentine, the thick balsam from larch trees, appeared in anti-inflammatory ointments alongside other natural resins. Chemical analysis of historical pharmaceutical formulations has confirmed the presence of Venetian turpentine mixed with other plant-based resin exudates, consistent with recipes documented in period pharmacopeias.¹³ Turpentine-based liniments were rubbed on the chest for respiratory complaints and on joints for rheumatic pain, and diluted turpentine was sometimes administered internally as an antiseptic or vermifuge (a treatment for intestinal worms).

Whether any of these old applications had genuine therapeutic value is debatable. Some monoterpenes found in turpentine do show antimicrobial and anti-inflammatory activity in laboratory settings, but the gap between a test-tube result and a safe, effective medicine is enormous. Modern pharmacology has moved on to isolated, dose-controlled compounds rather than crude plant extracts whose composition varies from batch to batch.

What Happens to Turpentine in the Environment

Turpentine’s terpene components are natural products, and the microbial world has had millions of years to figure out how to eat them. Soil bacteria, particularly species of Pseudomonas, can metabolize alpha-pinene and beta-pinene as their sole source of carbon and energy. One well-studied soil bacterium converts these pinenes through a cascade of intermediate compounds, including limonene and para-cymene, eventually breaking them down completely.¹⁴ The same organism can tolerate pinene concentrations up to 10 percent without growth inhibition, which is a remarkably high tolerance for a volatile organic compound.¹⁵

These bacteria are not just a curiosity. They have practical potential for bioremediation of turpentine-contaminated wastewater from resin processing and pulp mills. Researchers have also found that similar Pseudomonas strains living in natural pine resin carry genetic clusters for degrading diterpenes, the heavier resin acids that make up rosin.¹⁶ The broader implication is that an entire microbial ecosystem has co-evolved with conifer resin, and we are only beginning to catalog the biochemical pathways involved. Some of those pathways produce intermediate compounds with pleasant aromas, like perillic acid from limonene, which have potential uses in the fragrance and pharmaceutical industries. In early fermentation stages, cultures of pinene-degrading bacteria produce a distinct pine-like aroma that shifts to a rose-like scent as the breakdown progresses.¹⁵ Harnessing this kind of microbial biotransformation could eventually offer a “green chemistry” route to aroma chemicals that currently require harsher synthetic methods.