Balsam is a naturally fragrant, resinous substance exuded from the bark of specific trees and plants. This viscous material is an oleoresin, meaning it is a solution of resin in a volatile oil, which gives it strong, aromatic qualities. Its use spans diverse fields, from ancient healing practices to modern industrial and artistic applications.
Botanical Sources and Chemical Composition
Balsams are categorized by their botanical origin and chemical makeup. The classic examples, considered “true” balsams, are Balsam of Peru and Tolu Balsam, both derived from varieties of the Myroxylon balsamum tree, native to Central and South America. Balsam of Peru originates primarily from the variety pereirae and is mainly harvested in El Salvador, despite its name suggesting a Peruvian origin. Tolu Balsam comes from the variety balsamum and is traditionally sourced from Colombia and Venezuela.
The true balsams are chemically defined by a high concentration of aromatic compounds, specifically cinnamic acid and benzoic acid derivatives. Balsam of Peru contains 50 to 60% of the balsamic ester benzyl cinnamate, along with benzyl benzoate and small amounts of vanillin. This composition of resinous esters and volatile oils results in a dark, viscous appearance and a complex, sweet aroma.
Other plant exudates, such as Copaiba Balsam and Canada Balsam, are also commonly referred to as balsams. Canada Balsam is an oleoresin obtained from the balsam fir tree, Abies balsamea, found in North America. While these common balsams lack the high levels of cinnamic and benzoic acids found in the true balsams, they share the physical structure of resin dissolved in essential oil.
Therapeutic Applications in Medicine
Balsams have a long history in traditional medicine, valued for their antiseptic, anti-inflammatory, and expectorant properties. Balsam of Peru has been historically applied to minor wounds and burns, leveraging its mild bactericidal action to reduce infection. It also helps accelerate the repair of scar tissue when applied to skin ulcers by acting as a capillary bed stimulant.
Tolu Balsam is prominently featured in many older cough and cold remedies because of its expectorant qualities. When administered, the components of the balsam help reduce mucous secretions and loosen phlegm, making it easier to expel from the lungs and airways.
Balsam preparations are also utilized topically to treat chronic skin conditions like eczema or minor cuts. The anti-inflammatory compounds in the resinous mixture help to soothe irritation and reduce redness associated with these dermatological issues.
Role in Fragrance and Perfumery
In the fragrance industry, balsam extracts function primarily as potent base notes and fixatives. The heavy molecular structure of the resinous compounds helps anchor lighter, more volatile scent molecules, significantly slowing their evaporation rate. This extends the overall longevity of a perfume on the skin.
The scent profile of balsams is complex, often described as warm, sweet, resinous, and possessing nuances of vanilla and amber. Balsam of Peru, with its rich, velvety sweetness, is frequently used to lend depth and a comforting texture to a composition. Tolu Balsam contributes a slightly spicier, warmer vanilla-like note that blends seamlessly with other lasting materials like tonka bean and benzoin.
Balsamic notes are foundational in creating the rich, enveloping character of several major fragrance families, notably oriental and chypre compositions. They provide a grounded quality to perfumes, often residing in the heart or base where they complement floral and vanilla facets.
Application as Resins and Mediums in Art
Balsams find distinct application in the visual arts and material sciences, where their physical properties are valued over their scent or medicinal qualities. Canada Balsam, derived from the balsam fir, has historically been used in oil painting as a component in varnishes and painting mediums. It functions as a plasticizer, enhancing the flow of the oil paint and contributing to a durable, transparent finish that resists crystallization and yellowing over time.
When diluted, Canada Balsam can be applied as a final varnish layer to oil paintings, drying to a clear, glossy, and non-amorphous film. The material’s unique optical qualities also made it a standard in scientific microscopy for over a century.
Canada Balsam was traditionally used as a permanent mounting medium for preparing microscope slides. Its refractive index, measured to be around 1.522, is nearly identical to that of glass. This optical similarity reduces light scattering when viewing a sample, allowing for clear, high-resolution observation of the specimen under the coverslip. Although modern synthetic resins have largely replaced it, Canada Balsam is still recognized for creating permanent slides.