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

1. Identity & Chemical Information

• Common Name(s): Geosmin
• IUPAC Name: (4S,4aS,8aR)-4,8a-dimethyl-decahydronaphthalen-4a-ol
• CAS Number: 23333-91-7
• FEMA Number: Data not found
• Other Identifiers: FL number not clearly reported; CoE number not clearly reported; IFRA reference not applicable
• Molecular Formula: C12H22O
• Molecular Weight: 182.31 g/mol
• Functional Groups and Structure–Odor Relevance: Geosmin is a bicyclic alcohol with a distinctive earthy odor. Its structure includes a decahydronaphthalene ring system, which is crucial for its characteristic scent. The presence of the hydroxyl group contributes to its solubility and interaction with olfactory receptors.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

Geosmin is renowned for its earthy, musty odor, reminiscent of freshly turned soil or beets. It is a potent odorant with a low detection threshold, often cited as being around 5 ng/L in water. This compound plays a significant role as an impact note in flavor and fragrance formulations, providing a sense of authenticity and naturalness. Its intensity can be overwhelming if not balanced correctly, making it a powerful tool for creating realistic earthy profiles in both flavors and fragrances.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

Geosmin is naturally produced by microorganisms, including cyanobacteria and actinomycetes, particularly in soil and aquatic environments. It is a byproduct of the decomposition of organic matter, often formed through the degradation of carotenoids. Geosmin's presence in water and soil contributes to the characteristic earthy smell after rain, known as petrichor. Its natural origin allows it to be classified under "natural flavor" or "natural fragrance" designations, depending on the source and extraction method.

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

4. Use in Flavors

Geosmin is used in flavor formulations to impart earthy, root-like notes, often in conjunction with beet, mushroom, or truffle flavors. It is typically employed in low concentrations, ranging from 0.01 to 0.1 ppm in finished products, to avoid overpowering other flavor components. Its stability can be affected by heat and pH, with a tendency to degrade under acidic conditions. Formulators must consider these factors to maintain the desired sensory profile in the final product.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

In the fragrance industry, geosmin is valued for its ability to add depth and realism to earthy and woody compositions. It is commonly used in trace amounts, often less than 0.01% in the final product, to enhance the natural character of perfumes and personal care products. Geosmin contributes primarily to the base notes due to its low volatility, providing a long-lasting earthy aroma that complements other fragrance components.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

• United States: Geosmin is not explicitly listed as a FEMA GRAS substance, but its use in flavors is generally accepted under natural flavoring guidelines.
• European Union: Under Regulation (EC) No 1334/2008, geosmin can be used as a natural flavoring substance, though specific FL number status is not clearly reported.
• United Kingdom: Post-Brexit, the UK aligns with EU regulations regarding natural flavoring substances.
• Asia: In Japan and China, geosmin's use is subject to general flavoring regulations, with no specific restrictions noted.
• Latin America: In Brazil and MERCOSUR countries, geosmin is used under general flavoring guidelines, with no specific regulatory challenges identified.

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 due to its natural occurrence in food. Dermal exposure in fragrances is unlikely to cause irritation or sensitization, and it is not listed as a restricted substance by IFRA. Inhalation exposure is minimal due to its low volatility, with no significant occupational hazards reported.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

Geosmin is a valuable material for its ability to impart authentic earthy notes, enhancing the realism of both flavors and fragrances. It synergizes well with other natural compounds, such as vetiver and patchouli, to create complex, multi-dimensional profiles. Formulators should be cautious of its potency, as overuse can lead to an undesirable musty character. It is often underutilized in formulations seeking to replicate natural environments or earthy tones.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on geosmin is well-established, particularly regarding its sensory characteristics and natural occurrence. While specific regulatory details and quantitative use levels are less documented, industry practices provide a reliable framework for its application. Known data gaps include precise regulatory listings and comprehensive toxicological evaluations, though current evidence supports its safe use.

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
• If complex natural material: includes section 5a (not applicable here)

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 2026-09-26 18:41:31 GMT (p2)