Thinner From Trees

While there is such thing as a turpentine or terebinth tree (Pistacia terebinthus, a relative of the pistachio), most turpentine in this country is collected from southern pines, often the longleaf (Pinus palustris) and loblolly (P. taeda) pines, and western species like ponderosa (P. ponderosa) and Jeffrey (P. jeffreyi) pines. Specialized turps with shorter lists of organic molecules are derived from other species.

Pure gum spirits
Pure gum spirits

The word “turpentine” is ultimately derived from the Greek terebinthine. The tree is native to the entire Mediterranean basin and has been a source of turpentine since the era of the Old Testament, where it is mentioned. The entire plant, which is a large shrub or small tree, gives off a pungent, medicinal odor.

Historically the oleoresin of pines was harvested by stripping the bark off several feet of the trunks and then cutting into the sapwood with a series of chevrons. The exuded liquid is collected in a V-shaped trough attached parallel to the freshest incision. It drains on an angle into a bucket.

The oleoresin is added to a distiller and the turpentine is drawn from the portion that is boiled off and collected by the condenser.

Harvesting oleoresin from pines.
Harvesting oleoresin from pines.

A more modern and mass-intensive method for turpentine production involves destructive distillation or “cracking.” In this process the wood is heated to over 400°F, which drives off the volatile organics, also breaking them down into smaller molecules (pyrolysis). The non-volatile carbon molecules become charcoal, activated charcoal or methanol. During the production of turpentine the solid substance left behind is called rosin.

The turpentine, rosin and other derivatives produced from living trees are referred to as “gum naval stores.” Those derived from the pulping of the wood and destructive distillation are called “sulfate or wood naval stores.”

Most people are probably familiar with turpentine for its use as a oil paint or varnish thinner. It is also used to clean up equipment, brushes and your hands after working with paint or varnish. In actuality, most turpentine that is manufactured is turned into a source of other products. Pine oil—which gives Pinesol and other similar cleaning products their “pine smell”—is one such product. Other fragrance or flavor products include camphor and menthol.

Turpentine making
Turpentine making

The starting molecules in the tree itself are terpenes, a type of aromatic hydrocarbon (molecules with alternating double and single bonds in rings). Different terpenes are found in various plants. They are constituents of the “essential oils” associated with these species, which are the source of many fragrances and flavors. The aroma of hops (and beer) is caused by a terpene.

Turpentine is toxic to drink or even inhale in large quantities, but turpentine oil in small quantities are used in alternative medical treatments. Turpentine oil is applied to the skin for joint pain, muscle pain, nerve pain, and toothaches. People sometimes breathe in (inhale) the vapors of turpentine oil to reduce the chest congestion that goes along with some lung diseases. Even small quantities should never been taken orally.

According to Jeanne Rose, a Yahoo Network contributor: “Turpentine is also used as a treatment for lice in some cases, if applied externally on the affected area. Although turpentine is toxic to ingest, there is no direct harm if applied to certain areas of the skin. We do not commonly use turpentine as a treatment for lice today but it still is effective and might be an ingredient in some lice treatment medications you use. Turpentine was often used in the ancient times as a remedy for just about anything, but since it can be harmful if ingested we have limited the medicinal uses of turpentine.”

Although the advent of paint thinner may have diminished the use of turpentine as a paint and varnish solvent, it has been used for a wide variety of purposes for decades. Witness the list of Warren C. Ward of the U.S. Agriculture Forest Service who found 50 uses for it in 1930.


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