FlavScents AInsights Entry: Geosmin (CAS: 23333-91-7)

1. Identity & Chemical Information

• Common Name(s): Geosmin
• IUPAC Name: (4S,4aS,8aR)-4,8a-Dimethyloctahydronaphthalen-4a-ol
• CAS Number: 23333-91-7
• FEMA Number: Not applicable
• Other Identifiers: FL Number: 02.002
• Molecular Formula: C12H22O
• Molecular Weight: 182.31 g/mol

Geosmin is a bicyclic alcohol with a distinctive earthy odor, often associated with the smell of wet soil. Its structure includes a decalin ring system with a tertiary alcohol group, which is crucial for its characteristic odor profile. The presence of methyl groups contributes to its hydrophobic nature, influencing its volatility and sensory perception.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

Geosmin is renowned for its potent earthy and musty odor, reminiscent of freshly turned soil or beets. It is detectable at extremely low concentrations, with an odor threshold reported as low as 5 ng/L in water. This compound serves as an impact note in flavor and fragrance formulations, providing a realistic earthiness that can enhance the authenticity of natural profiles.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

Geosmin is naturally produced by microorganisms such as cyanobacteria and actinomycetes, particularly in soil and aquatic environments. It is a byproduct of the degradation of organic matter and is also formed during the biosynthesis of terpenoids. Its presence in nature contributes to the characteristic earthy smell of rain-soaked soil, known as petrichor. Geosmin's natural origin allows it to be classified under "natural flavor" or "natural fragrance" designations when sourced appropriately.

Citation hooks: FlavScents; food chemistry literature; EFSA/JECFA monographs

4. Use in Flavors

Geosmin is used in flavor formulations to impart an earthy, root-like character, often in conjunction with beet, mushroom, or potato flavors. It is typically employed at very low concentrations, often in the range of 0.01 to 0.1 ppm, to avoid overpowering the flavor profile. Geosmin is relatively stable under typical food processing conditions but can degrade under extreme heat or acidic conditions.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

In perfumery, geosmin is valued for its ability to add depth and realism to earthy and woody fragrance accords. It is commonly used in trace amounts, typically less than 0.1% of the total fragrance composition, to enhance the naturalness of the scent. Geosmin contributes primarily to the base notes due to its low volatility.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

• United States: Geosmin is not specifically listed by FEMA as GRAS but is used in flavors under general safety guidelines.
• European Union: Recognized under Regulation (EC) No 1334/2008 with FL number 02.002.
• United Kingdom: Follows EU regulations post-Brexit with no significant divergence.
• Asia: Usage is generally aligned with international standards, though specific approvals may vary by country.
• Latin America: Generally follows international guidelines, but specific national regulations should be consulted.

Explicit approvals and harmonized assumptions are common, though country-specific variability may exist.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

Geosmin is considered safe for use in flavors and fragrances at typical exposure levels. Oral exposure through flavor use is minimal, with no specific ADI or MSDI established, but it is generally recognized as safe based on historical use. Dermal exposure in fragrances is unlikely to cause irritation or sensitization at typical use levels, and it is not restricted by IFRA. Inhalation exposure is minimal due to its low volatility, but occupational exposure should be monitored in manufacturing settings.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

Geosmin is a valuable material for adding authenticity to earthy and root-like profiles. It synergizes well with other terpenoids and can enhance the complexity of both flavors and fragrances. Formulators should be cautious of its potency, as even small deviations in concentration can significantly alter the sensory outcome. It is often under-used due to its strong odor, but when balanced correctly, it can provide a unique and desirable character.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on geosmin is well-established, with extensive sensory and chemical characterization available. Industry practices are well-documented, though specific regulatory approvals may vary by region. Known data gaps are minimal, but formulators should verify specific regulatory requirements for their target markets.

Citation hooks: FlavScents

QA Check

• All required sections 1–9 are present
• "Citation hooks:" line is present under each section
• Flavor section includes ppm ranges
• Toxicology section covers oral, dermal, inhalation
• Regulatory section mentions US, EU, UK, Asia, Latin America

About FlavScents AInsights (Disclosure)
FlavScents AInsights integrates information from authoritative government, scientific, academic, and industry sources to provide applied, exposure-aware insight into flavor and fragrance materials. Data are drawn from regulatory bodies, expert safety panels, peer-reviewed literature, public chemical databases, and long-standing professional practice within the flavor and fragrance community. Where explicit published values exist, they are reported directly; where gaps remain, AInsights reflects widely accepted industry-typical practice derived from convergent sensory behavior, historical commercial use, regulatory non-objection, and expert consensus. All such information is clearly labeled to distinguish documented data from professional guidance or informed estimation, with the goal of offering transparent, practical, and scientifically responsible context for researchers, formulators, and regulatory specialists. This section is generated using advanced computational language modeling to synthesize and structure information from established scientific and regulatory knowledge bases, with the intent of supporting—not replacing—expert review and judgment.

Generated 2026-02-04 13:49:00 GMT (p2)