Birch Tar Oil

Technical Ingredient Overview

• 🌎 Origin — Sourced from distillers in Russia, Scandinavia, and Central Europe

• 🧪 Synonyms — Betula Alba Tar, birch wood tar, rectified birch tar oil

• 🧬 Chemical Formula — Complex mixture; no single formula (rich in phenols and aromatic hydrocarbons)

• 📂 CAS — 8001-88-5

• ⚖️ MW — Variable; dependent on fraction (complex mixture)

• 📝 Odor Type — Smoky–Leathery–Phenolic

• 📈 Odor Strength — Very strong

• 👃🏼 Odor Profile — Tarry, burnt leather, phenolic, medicinal, animalic

• ⚗️ Uses — Leather accords, smoky chypres, vintage reconstitutions, animalic effects

• 🧴 Appearance — Dark, viscous liquid; may be black or deep brown

What is Birch Tar Oil?

Birch tar oil is a historically used natural material obtained through pyrolysis of birch bark and wood, typically Betula pendula or Betula pubescens. Its complex odor profile contributes leathery, burnt, and phenolic nuances to perfumery. While now highly restricted, it remains culturally symbolic in leather-themed fragrances.

Historical Background

Evidence of birch tar use extends back to Neolithic civilizations, where it was applied as a glue, antiseptic, and waterproofing resin (Wrage, 2019). In perfumery, it gained prominence in early 20th-century masculine and leather creations, particularly those classified as Russian leather perfumes. Key examples include “Cuir de Russie” and “Bandit,” where birch tar shaped their raw, smoky character (Arctander, 1960).

Olfactory Profile & Perfumery Applications

Birch tar oil is characterized by its dark, smoky odor with leathery and phenolic dimensions. It is primarily active in the heart and base of compositions due to its low volatility. Trace amounts (~0.01–0.2%) are sufficient for a perceptible leathery nuance, while higher dosages (up to 2%) were historically used in classic formulations.

Typical uses include:

• Leather accords (Russian leather type)

• Smoky balsamic blends

• Chypre and woody-oriental structures

• Castoreum/styrax substitution in animalic effects

Due to toxicological concerns, modern use favors rectified fractions or synthetic reconstitutions to emulate the iconic olfactory effect without regulatory complications.

Industrial & Technical Uses

Outside perfumery, birch tar has seen use as a veterinary balm, insect repellent, and antiseptic. In historical contexts, it was also used in waterproofing leather and wood, and as a folk remedy for skin conditions.

Regulatory & Safety Overview

Birch tar oil is among the most restricted natural materials in perfumery due to its potential carcinogenic and sensitizing properties.

• IFRA: Prohibited in crude form; permitted only in highly rectified fractions under strict limits (IFRA, 2023)

• SCCS: Classified as a Category 1 carcinogen (SCCS, 2008)

• ECHA: Listed as hazardous due to presence of polycyclic aromatic hydrocarbons (PAHs) (ECHA, 2024)

• Allergenicity: Contains cresols, catechols, and phenols—recognized contact allergens

• EU Cosmetic Regulation: Mandatory labeling if thresholds exceeded

• Use Level: Typically <0.01% in finished products after rectification

Synthetic replacements are widely used to achieve regulatory compliance without compromising olfactory effect.

Environmental and Sustainability Aspects

• Sourcing: Primarily from birch forests in Europe and Russia

• Sustainability: Non-renewable at industrial scale; destructive distillation limits ecological viability

• Environmental Impact: Contains persistent compounds; improper disposal risks soil and water contamination

• Green Chemistry Shift: Increasing adoption of synthetic analogs aligns with sustainable formulation principles

Conclusion

Birch tar oil remains an emblematic perfumery material despite modern restrictions. Its raw, leathery scent profile has shaped some of perfumery’s most iconic accords. Today, its legacy is preserved through controlled rectified fractions and olfactively faithful synthetic substitutes, allowing perfumers to evoke its powerful character within safe, compliant frameworks.

Sources

• Arctander, S. (1960). Perfume and Flavor Materials of Natural Origin. Allured Publishing.

• ECHA. (2024). Substance Information – Birch Tar Oil (CAS 8001-88-5). https://echa.europa.eu/

• IFRA. (2023). IFRA Standards – 51st Amendment. International Fragrance Association. https://ifrafragrance.org/

• SCCS. (2008). Opinion on Birch Tar (SCCP/1176/08). European Commission, Scientific Committee on Consumer Safety.

• Sell, C. (2020). Fragrance Chemistry: The Science of the Sense of Smell. Royal Society of Chemistry.

• Surburg, H., & Panten, J. (2016). Common Fragrance and Flavor Materials (6th ed.). Wiley-VCH.

• Wrage, N. (2019). Birch Tar: Archaeological Use and Chemical Composition. Journal of Archaeological Science, 107, 76–85.