This section provides an overview of sotolone (caramel furanone), covering its manufacturing processes and regulatory status, applications in food flavouring, beverage production, and fragrance formulations. Also, please check out the introduction to caramel furanone manufacturers, supply chain issues, sotolone suppliers, and sotolone prices. Sinofi can help you buy sotolone at bulk wholesale prices based on FEMA 3634 and CAS 28664-35-9.
Table of Contents
What is Sotolone (Caramel Furanone)?
Sotolone, also known as caramel furanone or sugar lactone, represents a remarkably potent aroma compound that plays a crucial role in the food, beverage, and fragrance industries. This lactone belongs to the furanone family. Sotolone is scientifically known as 4,5-dimethyl-3-hydroxy-2,5-dihydrofuran-2-one. Due to its sweet, burnt-sugar scent, this lactone compound is responsible for some of the most beloved and complex flavours in culinary traditions worldwide. Its molecular structure—a five-membered heterocyclic lactone ring with hydroxyl and methyl substituents—provides exceptional thermal stability and volatility characteristics suited to vaping applications. The compound readily vaporizes at typical e-cigarette operating temperatures between 200-300°C without significant thermal degradation. According to the U.S. Food and Drug Administration (FDA), sotolone is approved to be used in the flavour, fragrance, and food industries.
Regulatory Status and Safety Considerations
Sotolone has been evaluated by relevant regulatory authorities like JECFA, EFSA, RIFM, ECHACHEM, NIST, and WHO. It holds Generally Recognized as Safe (GRAS) status in the United States when used in accordance with good manufacturing practices. The compound appears on the Flavour and Extract Manufacturers Association (FEMA) list with FEMA number 3634. In the European Union, it is approved for use as a flavouring substance under the Commission Implementing Regulation (EU) No 872/2012. As with all flavour ingredients, formulation engineers should verify current regulatory status in their specific markets and ensure compliance with applicable maximum use levels and labeling requirements. The fragrance standard of caramel furanone has been set by organizations such as IFRA.
Natural Occurrence and Sources
Sotolone occurs naturally in a surprising variety of foods and plants. It is a key aroma contributor in aged sake and sherry, where it develops through oxidative aging processes. The compound is also found in dried fenugreek seeds, lovage, molasses, aged rum, and certain coffees. During the Maillard reaction—the chemical process responsible for browning in cooked foods—sotolone forms as a byproduct, contributing to the complex flavours of roasted and caramelized products.
Sensory Profile and Flavour Characteristics
Sotolone exhibits an extraordinarily low odor detection threshold, typically cited between 0.3 and 1 parts per billion in water, making it one of the most potent flavour compounds encountered in formulation work. This exceptional potency demands careful handling and precise dosing during application. The sensory profile of sotolone is complex and concentration-dependent, displaying characteristics that range from maple syrup, caramel, and brown sugar at lower concentrations to curry-like, fenugreek, and lovage notes at higher levels. This dual nature provides formulation engineers with significant versatility, though it also requires careful attention to dosage levels to achieve the desired flavour direction.
CAS No.: 28664-35-9
According to the American Chemical Society, the CAS number of sotolone is 28664-35-9.
CAS Name: 4,5-Dimethyl-3-hydroxy-2,5-dihydrofuran-2-one
Molecular Formula: C6H8O3
Molecular Mass: 128.13
Appearance: Colorless to light yellow, clear liquid.
JECFA Number: 243
Food Chemicals Codex Listed: No
Melting Point: 25.00 to 29.00 °C. @ 760.00 mm Hg
Boiling Point: 93.00 to 95.00 °C. @ 2.00 mm Hg
Solubility: Soluble in alcohol and insoluble in water.
Other Names:
♦ Sotolone
♦ Sautalone
♦ Sotolon
♦ Caramel furanone
♦ Sugar lactone
♦ 3-Hydroxy-4,5-dimethyl-2(5H)-furanone
♦ 3,4-Dimethyl-2-hydroxy-2-butan-1,4-olide
♦ 4,5-Dimethyl-3-hydroxy-2(5H)-furanone
Caramel Furanone Odor
Odor Strength: Very high, recommend smelling in a 1.00 % solution or less.
Substantivity: > 400 hour(s) at 3.00 % in propylene glycol.
Odor Description: At 1.0 % in propylene glycol, extremely sweet, strong caramel, maple, burnt sugar, coffee.
FEMA Number 3634
According to the Flavor and Extract Manufacturers Association (FEMA), the number of 4,5-dimethyl-3-hydroxy-2,5-dihydrofuran-2-one (sotolone) is FEMA 3634.
Bulk Caramel Furanone (Sotolone) Manufacturers
The sotolone manufacturing divides into several distinct categories of suppliers, each serving different market needs and customer segments. Top sotolone manufacturers like Firmenich and Givaudan typically produce the compound through synthetic routes and serve major flavour houses and food manufacturers requiring consistent supply, rigorous quality control, and comprehensive regulatory documentation. Specialized flavour and fragrance ingredient manufacturers constitute another important category of suppliers. These companies focus specifically on aroma chemicals and often maintain deeper technical expertise in application development alongside their manufacturing capabilities. They typically offer additional services such as custom formulation support, application testing, and technical consultation that extend beyond simple chemical supply. Their customer base often includes mid-sized flavour houses and regional food manufacturers seeking more personalized service and technical partnership.
China has emerged as a dominant force in bulk sotolone production over the past two decades, driven by lower production costs, established chemical manufacturing infrastructure, and growing technical capabilities. Chinese caramel furanone manufacturers have invested substantially in quality systems and international certifications to serve export markets, particularly in Europe and North America.
Sinofi is a bulk sotolone manufacturer in China, and we have a manufacturing facility with 2,500 square meters for the production of caramel furanone solution. We supply high-quality sotolone at bulk prices and serve clients in food flavouring, beverage production, and fragrance formulations worldwide.
Manufacturing Process of Caramel Furanone (Sotolone)
The chemical manufacturing of sotolone requires integration of synthetic chemistry knowledge with practical process considerations to achieve consistent production of material meeting quality specifications at acceptable economics. The most widely employed commercial route involves the condensation of diacetyl (2,3-butanedione) with ethyl pyruvate or related alpha-keto esters under basic conditions. This approach offers advantages in terms of starting material availability, reasonable yields, and relatively straightforward reaction conditions that translate effectively to industrial-scale operations. The reaction proceeds through an aldol-type condensation mechanism, followed by cyclization and dehydration to form the characteristic furanone ring system that defines sotolone’s structure.
An alternative synthetic approach utilizes the reaction between acetoin (3-hydroxy-2-butanone) and diethyl oxalate or related oxalate derivatives. This route similarly relies on condensation chemistry but approaches the target structure through a different starting point. The choice between these routes often reflects factors including raw material costs and availability, production scale requirements, existing plant infrastructure and capabilities, and the specific quality specifications required for the intended market applications.
A third synthetic pathway involves the reaction of diacetyl with glyoxylic acid or its derivatives. This approach can proceed under acidic or basic catalysis, depending on the specific reaction design, and offers certain advantages in terms of atom economy and potential yields. However, the handling and storage requirements for glyoxylic acid derivatives sometimes present practical challenges that influence route selection decisions for commercial production.
Bulk Caramel Furanone (Sotolone) Suppliers
The global supply for caramel furanone demonstrates clear segmentation based on production scale, geographic footprint, and service capabilities. Top sotolone suppliers like Firmenich and Givaudan typically maintain annual production capacities measured in several hundred kilograms, operate multiple manufacturing facilities across different regions, and serve global customer bases, including major flavour houses and multinational food corporations. Chinese caramel furanone suppliers have established dominant positions in global sotolone production over the past fifteen years. They have invested heavily in quality systems and international certifications to meet Western market requirements.
Sinofi is a bulk sotolone supplier in China, and we have a warehouse with 1,200 square meters for high-quality caramel furanone. We sell different grades of sotolone at wholesale prices, serving end-users in food flavouring, beverage production, and fragrance formulations.
Supply Chain of Caramel Furanone (Sotolone)
This multi-tiered structure involves participants ranging from large petrochemical companies providing raw materials to specialized aroma chemical manufacturers, distributors facilitating market access, flavour houses creating formulations, and food corporations producing finished consumer goods. The foundation of the sotolone supply chain begins with the procurement of key chemical precursors required for synthesis. The primary raw materials include diacetyl, also known as 2,3-butanedione, which serves as a fundamental building block in the most common synthetic routes to sotolone. Pyruvate derivatives constitute another critical raw material input for sotolone synthesis. Manufacturers operate production facilities ranging from multi-purpose batch plants capable of producing various aroma chemicals to dedicated sotolone production lines in facilities specializing in furanone compounds. The distribution tier of the sotolone supply chain encompasses the activities and infrastructure required to move finished product from manufacturing facilities to customers worldwide. This stage involves warehousing, inventory management, transportation logistics, regulatory compliance for international trade, and often includes intermediary distributors who facilitate market access for manufacturers. The downstream portion encompasses the customer organizations that purchase bulk material and incorporate it into finished products. The primary customer segment consists of flavour houses. Food and beverage manufacturers represent a secondary customer segment, though most purchase sotolone indirectly as a component of complete flavour systems rather than directly as a raw material.
Wholesale and Buy Caramel Furanone (Sotolone) in Bulk
Successful wholesale procurement of sotolone requires integrating multiple considerations spanning supplier evaluation, quality assurance, contract management, inventory optimization, and relationship development. Caramel furanone buyers must balance cost objectives with reliability requirements, recognizing that the lowest price rarely represents the best value when quality consistency and supply continuity matter critically.
Defining Bulk Purchasing Requirements
The first step in developing an effective bulk procurement strategy involves clearly defining organizational requirements across multiple dimensions. Volume requirements must be established through careful analysis of historical consumption patterns, growth projections, and inventory policy decisions. Quality specifications require precise definition to ensure that procured material meets the technical requirements of its intended applications.
Supplier Evaluation and Selection Process
Identifying and evaluating potential suppliers represents perhaps the most critical activity in establishing effective bulk procurement arrangements. The sotolone suppliers include manufacturers with direct production capabilities and distributors who source from manufacturers and provide value through market access, inventory holding, and customer service. Initial supplier screening should assess basic capability and suitability across several dimensions. Production or distribution capacity must be sufficient to meet volume requirements reliably, with appropriate safety margins to accommodate growth or unexpected demand increases.
Quality Assurance and Specification Management
Establishing comprehensive quality assurance frameworks represents a critical responsibility for purchasing managers procuring bulk sotolone. Begin by documenting detailed specifications that define all relevant quality parameters, including minimum purity levels typically ninety-five percent or higher by gas chromatography, maximum limits for specific impurities that might affect performance or safety, organoleptic characteristics describing expected odor profile and intensity, and physical properties such as appearance and melting point range. Specifications should reference standard test methods where industry standards exist, or provide detailed methodology descriptions for proprietary tests.
As a bulk sotolone manufacturer and supplier in China, we wholesale this ingredient to end users in food flavouring, beverage production, and fragrance formulations. We also supply caramel furanone to small customers. Normally, they want to buy sotolone in small quantities. To serve them, we can sell sotolone at bulk prices and provide a one-stop purchasing service.
Caramel Furanone (Sotolone) Prices (USD/Kg)
Food Grade Caramel Furanone (Sotolone) Prices (GC Content >=98.0%)
| Volume | Unit Price | Shipment |
| 50g | 154 USD | Express |
| 500g | 770 USD | Express |
| 1Kg | 1300 USD/Kg | Express |
| 20Kg | 25% cheaper | Express |
| 100Kg-Above | negotiable | Express / Sea |
Sotolone (caramel furanone) trades at dramatically different price points depending on grade and source.
Current Price Ranges and Market Overview
The sotolone market exhibits pronounced price segmentation based on grade, certification status, and geographic origin. Current wholesale pricing from established sotolone distributors ranges from $1,300-1,600 per kilogram for synthetic food grades. Chinese sotolone manufacturers offer substantially lower prices for bulk quantities, with pricing dependent on order volume and delivery terms.
The most significant price premium applies to natural-origin sotolone. Sigma-Aldrich quotes natural food-grade sotolone (≥97% purity) at approximately $870 for 100g quantities. This natural versus synthetic price differential reflects the difficulty of extracting sotolone from fenugreek seeds—the primary natural source—where mass production via extraction remains commercially unviable.
Furthermore, the above sotolone price quotations do not include the express shipping fee. The reason is that the shipment cost of caramel furanone may exceed the sample value. However, the bulk wholesale prices of sotolone will be much lower than those of small orders. Please contact us for more details.
Caramel Furanone (Sotolone) Specification
| Appearance: | Colorless to light yellow, clear liquid. |
| Odor: | Sweet, caramel, maple, and brown sugar aromas. |
| Purity (GC) | >=98% |
| Refractive Index (20°C) | 1.4800-1.5200 |
| Specific Gravity (25°C) | 1.1050-1.2500 |
| Heavy Metal (as Pb, mg/Kg) | <=10 |
| As (mg/Kg) | <=3 |
Caramel Furanone (Sotolone) Uses
Sotolone Applications in the Food Industry
The food industry relies heavily on sotolone for flavour enhancement and creation. Its primary applications include:
- Maple-flavoured products represent one of the largest commercial uses. Since natural maple syrup is expensive and supply-limited, caramel furanone serves as a cornerstone ingredient in artificial maple flavourings used in pancake syrups, candies, and baked goods.
- Caramel and butterscotch flavours benefit from caramel furanone’s ability to round out and deepen sweet, burnt-sugar profiles.
- Confectioners and flavour chemists frequently incorporate it into candy formulations and dessert toppings.
- Savory applications take advantage of caramel furanone’s curry-like notes at higher concentrations. It appears in seasoning blends, soup bases, and meat flavourings where a warm, spicy depth is desired.
- Beverage formulation utilizes caramel furanone in coffee flavourings, certain liqueur recipes, and non-alcoholic drinks seeking aged or complex taste profiles.
Sotolone Applications in the Fragrance Industry
Perfumers value sotolone for its ability to add warmth and gourmand qualities to fragrances. It appears in perfumes seeking sweet, edible-smelling accords and serves as a modifier that can enhance and fix other aromatic ingredients. The compound’s dual nature—sweet at low doses, spicy at higher ones—gives formulators flexibility in creating layered scent profiles.
Caramel Furanone (Sotolone) Benefits
Exceptional Cost Efficiency Through Ultra-Low Dosing Requirements
The primary economic benefit of sotolone stems from its extraordinary potency, which translates directly to cost advantages in commercial formulations. Where conventional flavouring agents might require additions of 0.1% to 1% by weight, caramel furanone achieves comparable or superior sensory impact at concentrations between 1 and 100 ppm. This thousand-fold reduction in dosage creates multiple downstream benefits.
Manufacturing operations benefit from reduced raw material inventory requirements, as small quantities serve extensive production runs. A single kilogram of caramel furanone can flavour approximately 10,000 to 1,000,000 kilograms of finished product, depending on the application, dramatically reducing per-unit ingredient costs. Transportation and storage costs decrease proportionally, as does the carbon footprint associated with ingredient logistics.
Versatility Enables Multi-Application Development Efficiency
Sotolone’s concentration-dependent aroma characteristics provide unusual flexibility for product development teams. The same ingredient delivers savory, spicy, and curry-like notes at higher concentrations while producing sweet maple, caramel, and butterscotch impressions at trace levels. This dual functionality allows manufacturers to maintain leaner ingredient portfolios while addressing diverse product categories.
Food manufacturers developing both sweet and savory product lines can utilize a single high-quality aroma compound across multiple formulations rather than sourcing separate ingredients for different applications. This consolidation reduces supplier management overhead, simplifies procurement processes, and often improves negotiating leverage through increased order volumes with fewer vendors.
Minimal Sensory Interference With Base Product Characteristics
Unlike some potent flavouring agents that impose dominant characteristics regardless of concentration, caramel furanone integrates harmoniously into complex flavour systems when properly dosed. The compound functions as a flavour enhancer and modifier rather than a primary flavour driver in many applications, enriching existing taste profiles without overwhelming them.
Diagnostic and Analytical Applications Provide Quality Assurance Value
Sotolone serves important functions in quality control and product authentication. The compound’s formation during oxidative aging provides a measurable marker for assessing wine quality, detecting premature oxidation, and verifying age claims in premium products. The compound’s role as a diagnostic marker for maple syrup urine disease demonstrates its utility in medical applications beyond food and fragrance. This expands the market for high-purity caramel furanone standards and creates additional revenue streams for manufacturers capable of producing pharmaceutical-grade material meeting stringent purity specifications.
Caramel Furanone (Sotolone) in E-Liquid and Vaping Products
Caramel furanone has emerged as a significant flavouring ingredient in the e-liquid and vaping industry. This powerful lactone compound, with an odor detection threshold as low as 0.8 micrograms per liter, enables e-liquid formulators to create authentic maple, caramel, tobacco, and dessert profiles at minimal concentrations.
Core Applications in E-Liquid Flavour Formulations
Sotolone serves multiple functional roles across e-liquid flavour categories, with applications spanning both nicotine-containing and nicotine-free products designed for various vaping devices and consumer preferences.
Tobacco Flavour Profiles
The compound features prominently in tobacco e-liquid formulations, particularly the popular RY4 style that originated from early Chinese e-cigarette development. RY4 formulations—named for “Ruyan blend number 4” from the pioneering manufacturer—combine tobacco base notes with caramel and vanilla sweetness. Sotolone contributes essential caramelized depth at typical concentrations between 3 and 15 ppm, bridging tobacco’s inherent dryness with the required sweetness consumers expect from this classic profile.
Beyond RY4, caramel furanone appears in various tobacco formulations, including Virginia blends, dark-fired tobacco recreations, and cigar-inspired profiles. In Virginia tobacco e-liquids, formulators employ caramel furanone at 2-5 ppm to add natural sweetness reminiscent of bright-leaf tobacco’s inherent sugar content. Dark tobacco formulations utilize higher concentrations around 10-20 ppm, where caramel furanone’s more pronounced caramel-molasses character complements the robust base notes. Cuban cigar and premium tobacco profiles often incorporate caramel furanone at 5-10 ppm alongside other aged tobacco modifiers to suggest barrel aging and fermentation character.
The compound proves particularly valuable for tobacco formulations targeting former cigarette smokers, as the added sweetness and complexity help bridge sensory expectations while differentiating the vaping experience from combustible tobacco.
Maple Syrup and Breakfast Flavour Systems
Maple syrup represents one of sotolone’s most straightforward applications in e-liquid formulation. The compound serves as the primary maple character contributor at concentrations typically between 10 and 30 ppm, often supplemented with brown sugar notes, vanillin, and buttery modifiers to create full maple syrup profiles. Single-note maple e-liquids aimed at simplicity and authenticity may rely almost exclusively on caramel furanone, while more complex breakfast formulations layer additional components.
Pancake and waffle e-liquids combine sotolone-driven maple character with bready, buttery, and custard notes. Formulators typically employ caramel furanone at 15-25 ppm in these applications, balancing sweet maple impressions against bakery base notes. French toast formulations follow similar approaches, with sotolone contributing maple-caramel sweetness alongside cinnamon, vanilla, and eggy custard modifiers. The breakfast category has gained significant market traction, with consumers appreciating dessert-like sweetness in morning vaping routines or as all-day options.
Caramel, Toffee, and Confectionery Applications
Pure caramel e-liquids utilize caramel furanone as a key component alongside traditional caramel flavouring materials. Typical formulations employ 8-20 ppm sotolone to enhance authentic burnt sugar character and add complexity beyond what standard caramel flavours alone provide. Salted caramel variations—among the most popular dessert e-liquid categories—incorporate caramel furanone at similar levels while adding sodium chloride or specialized salt flavours to create the characteristic sweet-savory balance.
Toffee and butterscotch profiles benefit from sotolone’s ability to suggest extended heating and caramelization. Formulators typically use 10-25 ppm in butterscotch formulations, where sotolone reinforces buttery sweetness with deep caramel undertones. English toffee and butter toffee variations employ similar concentrations, sometimes pushing toward 30 ppm when targeting a more intense burnt sugar character.
Candy and confectionery e-liquids, including caramel apple, caramel popcorn, and caramel nut combinations, all leverage sotolone’s contributions. In these applications, caramel furanone typically appears at 5-15 ppm, providing background complexity rather than dominant character.
Formulation Technical Considerations
Incorporating sotolone into e-liquid formulations requires attention to several technical factors that influence final product quality, consistency, and consumer experience.
Concentration and Dilution Management
Given sotolone’s extraordinary potency, most e-liquid manufacturers work with pre-diluted solutions rather than pure material. Common dilutions include 0.1%, 1%, and 3% in propylene glycol (PG), dipropylene glycol (DPG), or triethyl citrate (TEC). These pre-dilutions enable more accurate weighing and dosing while minimizing the risk of over-flavouring that can occur when attempting to measure milligram quantities of pure sotolone.
Formulators typically target final e-liquid concentrations between 1 and 30 ppm, depending on the application and desired intensity. A 10 ppm target concentration in finished e-liquid can be achieved by adding 1 gram of 1% caramel furanone solution per kilogram of e-liquid, or 0.333 grams of 3% solution per kilogram. Most formulations work within the 5-15 ppm range for balanced profiles, with only the most intense caramel or maple applications exceeding 20 ppm.
Solubility and Stability in VG/PG Systems
Sotolone demonstrates good solubility in both propylene glycol and vegetable glycerin (VG), the two primary base solvents used in e-liquid manufacturing. The compound’s moderate polarity allows it to remain fully dissolved across the range of VG/PG ratios commonly encountered in commercial e-liquids, from 50/50 blends popular in nicotine salt formulations to high-VG ratios (70/30 or 80/20) preferred for sub-ohm vaping.
Stability testing demonstrates that caramel furanone maintains its sensory characteristics throughout typical e-liquid shelf life expectations of 12-24 months when stored under appropriate conditions. The compound resists oxidation better than some other lactones and furanones, showing minimal degradation in accelerated aging studies. Exposure to elevated temperatures (40°C or higher) for extended periods can promote some loss of intensity, though this degradation remains less pronounced than with more volatile or chemically labile flavour compounds.
Interaction with Nicotine and Other E-Liquid Components
Sotolone demonstrates chemical compatibility with both freebase nicotine and nicotine salts at concentrations typically employed in e-liquids. The compound’s neutral pH characteristics mean it neither accelerates nicotine oxidation nor participates in acid-base reactions that might alter nicotine delivery characteristics. Some formulators report that sotolone’s caramelized sweetness helps mask nicotine’s inherent harshness at higher concentrations, potentially improving palatability in strength-forward formulations targeting heavy smokers.
Sweeteners, including sucralose, ethyl maltol, and steviol glycosides, can interact synergistically with caramel furanone, amplifying perceived sweetness beyond additive effects. Formulators must account for this interaction when employing both caramel furanone and dedicated sweetening agents, as the combination can create cloying profiles that fatigue the palate during extended vaping. Many experienced formulators reduce sweetener additions by 20-40% in sotolone-containing formulations to maintain an appropriate balance.
Cooling agents, including menthol, WS-23, and related compounds, do not chemically interact with caramel furanone but can suppress its perception through competitive trigeminal stimulation. Formulations combining sotolone with cooling require elevated concentrations—typically 1.5-2 times standard levels—to maintain equivalent caramel or maple impact. This consideration becomes particularly relevant for menthol tobacco and iced dessert formulations where both warming caramel notes and cooling sensations contribute to the target profile.
Regulatory Status Across Markets
In the United States, the FDA’s Premarket Tobacco Product Application (PMTA) process requires manufacturers to demonstrate that their products are “appropriate for the protection of public health.” Sotolone-containing e-liquids marketed in the U.S. must either secure PMTA authorization or qualify for enforcement discretion under applicable FDA policies.
The European Union’s Tobacco Products Directive (TPD) establishes compositional requirements for e-liquids but does not explicitly prohibit caramel furanone or most other FEMA GRAS flavouring substances. However, TPD requires notification of all ingredients and prohibits substances that pose health risks, increase toxicity, or have carcinogenic, mutagenic, or reprotoxic (CMR) properties. Manufacturers must maintain data supporting the safety of all ingredients included in e-liquids marketed within EU member states.
A Grape-Flavoured E-Liquid
Include the following ingredients (by weight):
Nicotine 1.1%, Grape essential oil 17.64%, Acetoin 0.9%, Massoia lactone 1.1%, Sotolone 0.8%, 2,3,5-Trimethylpyrazine 0.004%, Peppermint oil 8.3%, Propylene glycol 35.2%, and Glycerol 34.956%.
In conclusion, sotolone stands as an indispensable tool in the flavour formulation engineer’s repertoire, offering powerful caramel, maple, and fenugreek characteristics at extremely low use levels. As a bulk caramel furanone manufacturer and supplier in China, we sell different grades of sotolone at wholesale prices to clients around the world.