Ethyl Maltol vs. Maltol: Which Works Better in Perfumery?
1. Introduction
Among the many sweet-smelling molecules used in fragrance and flavor design, Maltol and its more potent cousin Ethyl Maltol occupy a special place. Both belong to the 4-pyrone family and are celebrated for their caramelic, candy-like notes. However, despite their similar structures, these compounds differ significantly in olfactory strength, volatility, usage patterns, and emotional evocation.
This Comparative Insight explores their technical and sensory divergences, helping perfumers and formulators make informed decisions based on performance and effect.
2. Structural & Chemical Comparison
2.1 Chemical Identity
Here's a detailed comparison of Maltol and Ethyl Maltol based on their core attributes.
IUPAC Name:
Maltol: 3-hydroxy-2-methyl-4H-pyran-4-one
Ethyl Maltol: 2-ethyl-3-hydroxy-4H-pyran-4-one
CAS:
Maltol: 118-71-8
Ethyl Maltol: 4940-11-8
FEMA:
Maltol: 2656
Ethyl Maltol: 3487
Molecular Formula:
Maltol: C₆H₆O₃
Ethyl Maltol: C₇H₈O₃
Molecular Weight:
Maltol: 126.11 g·mol⁻¹
Ethyl Maltol: 140.14 g·mol⁻¹
Key Structural Difference:
Maltol: Methyl (–CH₃) at C-2
Ethyl Maltol: Ethyl (–CH₂CH₃) at C-2
A single-carbon extension from a methyl to an ethyl side-chain increases the molecular weight by ~11 %, lowers volatility, and—critically—boosts odour potency by approximately one order of magnitude (Sell, 2006; PubChem, 2024).
2.2 Natural Occurrence
Natural Sources: Larch bark, roasted malt, chicory, baked bread crust, caramelised sugars
Typical Concentration: Up to 30 ppm in certain foods
Regulatory Status (EU): "Natural flavouring substance" (Reg. EU 1334/2008)
Natural Sources: No significant natural abundance; only trace thermal artefact
Typical Concentration: < 1 ppm
Regulatory Status (EU): Considered synthetic for regulatory purposes
Because Ethyl Maltol does not occur in meaningful amounts in nature, it is manufactured via multi-step chemical synthesis—typically starting from diketene or furfuryl alcohol—yielding > 99 % purity suitable for flavour and fragrance use (Stephens & Allingham, 1971).
A two-carbon difference, a world of olfactory impact.
Maltol delivers subtle “fresh-baked” warmth; Ethyl Maltol projects vivid cotton-candy sweetness at a fraction of the dosage.
3. Olfactory Differences & Odor Thresholds
3.1 Odour Strength & Qualitative Profile
Although both molecules share a caramel-sweet core, their perceived intensity and character diverge sharply. Maltol delivers a warm, bready caramel note, whereas Ethyl Maltol projects vivid cotton-candy and jammy-fruit tones at tiny dosages (Sell, 2006; Arctander, 1960).
3.2 Odour-Threshold Comparison
Here's a detailed look at the sensory characteristics of Maltol and Ethyl Maltol.
Odour Descriptor: Caramel, bread-crust, maple-like
Odour Threshold (air): ≈ 20 – 40 ppb
Perceived Intensity: Moderate*
Diffusion Phase: Mainly Heart → Base
Odour Descriptor: Cotton candy, jammy strawberry, burnt sugar
Odour Threshold (air): < 10 ppb
Perceived Intensity: Strong (≈ 10× maltol)*
Diffusion Phase: Top → Heart → Base (bridging)
Perceived intensity at equal molar concentration (Sell, 2006).
The one-carbon elongation in Ethyl Maltol lowers its odour threshold by roughly an order of magnitude, making it perceptible even in trace (< 10 ppb) concentrations (PubChem, 2024).
3.3 Diffusion Behaviour (Top–Heart–Base)
Appears mainly in the heart/base, adding mellow warmth and a subtle baked facet.
Limited projection; best for background softness.
Perceived from top-note burst through dry-down, acting as a diffusion booster.
Bridges sharp fruity top notes to lactonic or vanillic bases, giving a syrupy “glaze” effect.
Key Insight
Ethyl Maltol = high-definition sweetness.
Maltol whispers warm pastry; Ethyl Maltol shouts carnival candy at one-tenth the dose.
4. Usage in Perfumery & Flavor
Maltol and Ethyl Maltol diverge sharply in practical application. Maltol, with its gentle bread-crust warmth, is employed sparingly in fine fragrance but remains popular in bakery flavors, bouillon cubes, and maple-style syrups where a “fresh-from-the-oven” nuance is desired (Arctander, 1960).
Ethyl Maltol’s vivid cotton-candy signature, by contrast, has become a cornerstone of modern gourmand perfumery, appearing in youthful fruity scents, comforting ambers, and woody-oriental blends (Sell, 2006). Its extreme potency (0.05 – 0.30 % of concentrate) lets perfumers create a glossy sugar glaze without tipping the formula into cloying sweetness.
On the flavor side, Ethyl Maltol (FEMA 3487) is approved for confections, beverages, and e-liquids, where it boosts perceived sweetness and smooths sour edges. Maltol (FEMA 2656) still enhances caramel and malt notes but generally at 10× the dose required for Ethyl Maltol (FEMA, 2023).
4.1 Compatibility in Formulas
Here's a comparison of how Maltol and Ethyl Maltol perform and are typically used in different applications.
Typical Dosage (perfume concentrate): 0.2 – 1.0 %
Primary Olfactory Effect: Warm bread-crust, caramel
Main Flavor Applications: Bakery, broths, maple syrup
Projection / Diffusion: Low-moderate
Typical Dosage (perfume concentrate): 0.05 – 0.30 %
Primary Olfactory Effect: Cotton candy, jammy fruit
Main Flavor Applications: Confectionery, beverages, e-liquids
Projection / Diffusion: High (radiant)
4.2 Interacting with Other Ingredients
Here's how Maltol and Ethyl Maltol interact with different ingredient classes, influencing the final sensory profile.
Fruity Esters (e.g., Benzyl Acetate)
Effect with Maltol: Adds mellow caramel warmth
Effect with Ethyl Maltol: Creates glossy jam-like glaze
Lactones (γ- & δ-Undecalactone)
Effect with Maltol: Reinforces baked-dessert nuance
Effect with Ethyl Maltol: Builds creamy "strawberry-milk" effect
Vanillin / Coumarin
Effect with Maltol: Depth & light gourmand body
Effect with Ethyl Maltol: Amplifies Maillard warmth; high lift
Aldehydes C-14 / C-18
Effect with Maltol: Soft buffering
Effect with Ethyl Maltol: Sweetens & reduces harshness; risk of burnt tonality if overdosed
Formulation tip: When replacing Maltol with Ethyl Maltol, start at one-tenth the Maltol dosage and titrate upward in 0.02 % increments; the sensory curve is non-linear and quickly plateaus (Sell, 2006).
5. Performance in Formula
5.1 Fixation & Radiance
Although both molecules contribute sweetness, their behaviour inside a perfume concentrate differs markedly:
Works as a soft fixative, binding volatile esters and aldehydes to the mid-note and smoothing the transition into vanillic or lactonic bases.
Exhibits high diffusion: on a standard blotter (2 mg), a cotton-candy aura is still detectable after 72 h (Sell, 2006).
Lower volatility yet stronger projection allows a “sugar-glaze” effect audible through top, heart, and base.
Adds background warmth (caramel–bread nuance) mainly in the heart/base.
Diffusion is modest; odour often recedes to skin level within 24–48 h at equal molar loading.
Better for texture than radiance; high doses can dull bright fruit notes.
Rule of thumb: to match perceived sweetness, dose Ethyl Maltol at ~1 ⁄ 10 the Maltol level; expect ≥ 2× diffusion (Kraft & Bajgrowicz, 2004).
5.2 Market Usage Trends
Here's a breakdown of the market presence and trend insights for Maltol and Ethyl Maltol across various segments.
Fine Fragrance (top 250 SKUs)
Presence of Maltol: ≈ 2 %
Presence of Ethyl Maltol: ≈ 18 %
Trend Insight: Ethyl Maltol drives gourmand & fruity-floral launches; Maltol appears in niche "bakery" concepts.
Candles / Home Scent
Presence of Maltol: ≈ 8 %
Presence of Ethyl Maltol: ≈ 27 %
Trend Insight: Heat stability & throw favour Ethyl Maltol in bakery-style candles.
Flavor / E-liquid
Presence of Maltol: Moderate
Presence of Ethyl Maltol: Very high
Trend Insight: Potency and sugar-reduction potential make Ethyl Maltol dominant.
Supply-chain note: Industrial capacity for Ethyl Maltol (> 10 kt yr⁻¹) keeps cost competitive despite higher synthetic complexity. Maltol supply is smaller but stable, sourced partly from lignin and caramelisation side-streams (Across Biotech, 2022).
Supply-chain note: Industrial capacity for Ethyl Maltol (> 10 kt yr⁻¹) keeps cost competitive despite higher synthetic complexity. Maltol supply is smaller but stable, sourced partly from lignin and caramelisation side-streams (Across Biotech, 2022).
Key takeaway:
Ethyl Maltol = radiance + fixation + modern demand. Maltol remains valuable for subtle pastry warmth, but Ethyl Maltol is the go-to for low-dose impact and projection.
6. Safety, Regulation & Environmental Impact
Both Maltol and Ethyl Maltol enjoy broad regulatory acceptance. Yet their legal status and eco-toxicological data differ in details relevant to “clean” or eco-label projects.
6.1 IFRA / FEMA / REACH Status
Here's a comparison of the regulatory status of Maltol and Ethyl Maltol across various schemes.
IFRA (51st Amendment): Not restricted
FEMA GRAS No.: 2656
EU Cosmetics – Annex III allergen: Not listed
REACH Reg. No.: 01-2119903165-43
GHS Classification: Acute Oral Tox. Cat 4 (H302)
IFRA (51st Amendment): Not restricted
FEMA GRAS No.: 3487
EU Cosmetics – Annex III allergen: Not listed
REACH Reg. No.: 01-2120758795-36
GHS Classification: Acute Oral Tox. Cat 4 (H302)
6.2 Environmental Profile
Biodegradability (OECD 301): Readily (78 % / 28 d)
Aquatic LC₅₀ (96 h, fish): 36 mg L⁻¹
log K₀w: 1.2 (low bio-accumulation)
Henry Constant (volatility): Low
Biodegradability (OECD 301): Readily (71 % / 28 d)
Aquatic LC₅₀ (96 h, fish): 27 mg L⁻¹
log K₀w: 1.5 (low bio-accumulation)
Henry Constant (volatility): Slightly lower
Interpretation. Both molecules are readily biodegradable, show low bio-accumulation, and present only moderate acute aquatic toxicity at concentrations far above fragrance-use levels. Ethyl Maltol’s slightly lower volatility may reduce evaporative losses during candle or room-spray manufacture.
Safety Margin in Use
ADI (JECFA): 0–2 mg kg⁻¹ bw day⁻¹ for both molecules
Typical fragrance dose: ≤ 0.3 %; two–three orders of magnitude below the NOAEL reported for oral studies (Hekserij, 2024).
7. Summary Table & Application Scenarios
7.1 At a Glance: Maltol vs. Ethyl Maltol Comparative Summary
Here's a concise overview comparing Maltol and Ethyl Maltol across key criteria.
Odour Descriptor: Caramel, bread-crust
Odour Threshold (air): ≈ 20 – 40 ppb
Perfume Dosage: 0.2 – 1.0 %
Projection / Diffusion: Low – moderate
Creative Role: Warm pastry nuance
IFRA Restriction: None
FEMA GRAS No.: 2656
Industrial Cost Trend:* Lower $ / kg, higher dose
Odour Descriptor: Cotton candy, jammy fruit
Odour Threshold (air): < 10 ppb
Perfume Dosage: 0.05 – 0.30 %
Projection / Diffusion: High, radiant
Creative Role: Signature sweetness & boost
IFRA Restriction: None
FEMA GRAS No.: 3487
Industrial Cost Trend:* Higher $ / kg, 1⁄10 dose
Overall cost in finished formula often favours Ethyl Maltol due to its much lower inclusion level.
7.2 Application Scenarios & Formulation Tips
Let's explore specific scenarios where Maltol or Ethyl Maltol is the preferred molecule and why, along with practical tips.
Bakery “Fresh-Baked” Accord
Preferred Molecule: Maltol
Why: Toasty caramel warmth
Practical Note: Blend with cyclotene, maple lactone.
Gourmand Strawberry-Jam Accord
Preferred Molecule: Ethyl Maltol
Why: Vivid jammy sweetness & diffusion
Practical Note: Pair with γ-undecalactone at ≤ 0.15 %.
Comforting Amber Base
Preferred Molecule: Ethyl Maltol + Vanillin
Why: Sticky resinous glaze
Practical Note: Add trace Maltol for subtle pastry nuance.
Natural-leaning Pastry Perfume
Preferred Molecule: Maltol
Why: Plant-derived, "nature-identical"
Practical Note: Verify botanical sourcing for clean-label claims.
Sugar-Reduced Beverage Flavor
Preferred Molecule: Ethyl Maltol
Why: High sweetness, low calories
Practical Note: Typical 20–80 ppm in finished product.
Formulator’s shortcut
To modernise a Maltol-rich pastry accord, substitute 70–90 % of the Maltol with Ethyl Maltol, then fine-tune fruity esters so the top note does not become over-jammy (Sell, 2006).
8. Conclusion
Although Maltol and Ethyl Maltol share the same 4-pyrone backbone, they fulfil distinct roles in modern fragrance and flavour work. Maltol delivers a gentle, pastry-like warmth; Ethyl Maltol projects vivid carnival sweetness with striking diffusion at one-tenth the dose.
When to Choose Maltol vs. Ethyl Maltol
Here's a quick guide to help you decide which molecule is best suited for your specific needs, based on its unique characteristics and effects.
If you need …
Low-key gourmand depth in an otherwise natural formula
Reach for: Maltol
Because: It's nature-identical and adds warmth without overt candy facets.
If you need …
A radiant, jam-like glaze that carries from top to base
Reach for: Ethyl Maltol
Because: It has an approximately 10x lower odor-threshold and stronger diffusion for an instant gourmand signature.
If you need …
Maximum sweetness boost in food or e-liquids at minimal ppm
Reach for: Ethyl Maltol
Because: Its GRAS potency enables sugar reduction and cost-efficient flavor impact.
If you need …
Subtle caramel-bread nuance for niche “patisserie” accords
Reach for: Maltol + Cyclotene
Because: It blends smoothly with brown-sugar lactones and maple facets.
9. Regulatory & Environmental Note
Both molecules are IFRA-unrestricted, readily biodegradable, and show low bio-accumulation. Choice therefore hinges on creative intent, performance requirements, and dosage economics rather than compliance hurdles.
Bottom line:
Choose Maltol when you want tender, toasted comfort in the background.
Choose Ethyl Maltol when you want the cotton-candy lights to take centre stage.
References
Sell, C. (2006). The Chemistry of Fragrances: From Perfumer to Consumer (2nd ed.). Cambridge: Royal Society of Chemistry.
PubChem. (2024). Maltol (CID 6123) & Ethyl Maltol (CID 7789). National Center for Biotechnology Information. https://pubchem.ncbi.nlm.nih.gov
Arctander, S. (1960). Perfume and Flavor Chemicals (Aroma Chemicals). Montclair, NJ: Allured Publishing.
Stephens, C. R., & Allingham, R. P. (1971). Preparation and use of 2-ethyl-3-hydroxy-4-pyrone (Ethyl Maltol). U.S. Patent No. 3 585 263.
FEMA. (2023). GRAS Flavoring Substances 28. Flavor & Extract Manufacturers Association. https://www.femaflavor.org
Across Biotech. (2022). Ethyl Maltol Production and Suppliers. Retrieved from https://acrossbiotech.com/methyl-maltol-and-ethyl-maltol-manufacturers/
Kraft, P., & Bajgrowicz, J. A. (2004). Olfactory chemistry. Chemistry & Biodiversity, 1(9), 1364–1396. https://doi.org/10.1002/cbdv.200490104
ECHA. (2023). Registration Dossiers: Maltol; Ethyl Maltol. European Chemicals Agency. https://echa.europa.eu
IFRA. (2023). Index of IFRA Standards – 51st Amendment. International Fragrance Association. https://ifrafragrance.org
Joint FAO/WHO Expert Committee on Food Additives. (1999). Evaluation of Certain Food Additives and Contaminants (WHO Technical Report Series No. 891).
Hekserij. (2024). Safety Data Sheet: Ethyl Maltol. Retrieved from https://www.hekserij.nl/wp-content/uploads/2024/10/SDS-23147-Ethyl-Maltol-2024-05.pdf
