Quick Search
Potassium Stearate is the potassium salt of stearic acid and is identified by the registry entries CAS No 593-29-3 and EC No 209-786-1. With the molecular formula C₁₈H₃₅KO₂, this compound occurs as a white, fine powder or flakes with a slightly greasy feel. In the food field it is listed under the code E 470a in the group of salts of fatty acids and is used as an emulsifier, stabilizer and anticaking agent.
The potassium salt of stearic acid, this substance is an amphiphilic soap that carries a charged carboxylate group at one end and a long hydrocarbon chain at the other. This structure makes it easier for oil and water to mix, reduces the sticking of powders to one another and acts as a release agent on mold or tablet surfaces. It is slightly soluble in cold water and dissolves well in hot water.
E 470a, the food grade product is used in cake gel systems, margarine, non-dairy creams, sauces, powder mixes and tablets. It also takes part in cosmetics, soap, polymers and rubber. In selection, the fatty acid composition, free fatty acids, free alkali, moisture and heavy metal limits are decisive. This product can be supplied from ATAMAN KİMYA; for technical information and supply requests, it is recommended to contact ATAMAN KİMYA.
WHAT IS POTASSIUM STEARATE?
Potassium Stearate is a potassium soap formed by neutralizing stearic acid, a saturated fatty acid with 18 carbons, with potassium hydroxide. It is a salt of crystalline structure and, when dissolved in water, separates into the potassium cation and the stearate anion. Commercial products are in most cases mixtures of stearate and palmitate rather than pure stearate.
The reason for this is the source of the raw material. The stearic acid used in the food and cosmetic fields is a fatty acid mixture obtained from vegetable or animal fats and containing a significant proportion of palmitic acid. For this reason, commercial Potassium Stearate differs from one manufacturer to another in fatty acid composition, even if the product code stays the same.
As a food additive, E 470a is the common name of the sodium, potassium and calcium salts of fatty acids. In the EU specification, these salts are expected to be produced from fatty acids obtained from edible fats and oils. Potassium Stearate is one of the potassium salts of this group.
The substance is not extracted directly from a natural raw material; it is produced by reacting a fatty acid or a fat with potassium hydroxide. In the direct neutralization of the fatty acid, only water is formed as a by-product, whereas in the saponification of a fat, glycerol is released. The resulting soap is washed, dried and offered as powder, flakes or paste.
Potassium Stearate gives an alkaline solution in water and lowers surface tension thanks to its long-chain part that passes into the oil phase. These two properties are associated in food systems with effects such as pH adjustment, water retention, support for aeration and reducing oil-water separation.
When evaluating the product, different grades under the same name must be distinguished. For food grade, compliance with the E 470a specification, the source of the fatty acid and the relevant documents should be taken as the basis. Technical, cosmetic or laboratory grades may carry the same CAS number, but this does not mean they are suitable for use in food.
Potassium Stearate must not be confused with sodium stearate, calcium stearate and magnesium stearate. The sodium and potassium salts are soluble in water, whereas the calcium and magnesium salts are not. This difference directly determines in which system and with which function the product will be used.
COMMON PRODUCT AND CHEMICAL NAMES OF POTASSIUM STEARATE:
Potassium stearate
Stearic acid, potassium salt
Potassium octadecanoate
Octadecanoic acid, potassium salt
Potassium n-octadecanoate
Octadecanoic acid, potassium salt (1:1)
Potassium stearate soap
Food grade potassium stearate
Food additive E 470a
E 470a potassium stearate
INS 470(i)
Potassium salts of fatty acids
Hydrogenated fatty acid, potassium salt
Steadan 300
Kaliumstearat
Stéarate de potassium
Estearato de potasio
CH₃(CH₂)₁₆COOK
Pure potassium stearate
Potassium salt of octadecanoic acid
Potassium salt of stearic acid
Rexanol
Nonsoul MK 2
Potassium Stearate (INCI)
Most of these names express the same compound with different spellings and in different languages. Octadecanoate is the systematic name of the 18-carbon chain, while stearate is the common name. E 470a and INS 470(i) are the codes the product receives when it is used as a food additive.
One point to note is that most commercial products are not a pure compound but a mixture of stearate and palmitate. Some manufacturers sell this mixture under the name “Potassium Stearate”. It is also seen that different CAS and EC numbers are used for the potassium salts of C16–C18 fatty acids.
Steadan 300 is a trade name, and this name appears in registry databases as a synonym of Potassium Stearate. Even if trade names describe the same chemical structure, the fatty acid composition, particle form and additives may vary by manufacturer. For food use, the product documents must be requested separately.
The similarity of names can be misleading. Stearic acid (CAS No 57-11-4) is the free fatty acid, whereas sodium stearate (822-16-2), calcium stearate (1592-23-0) and magnesium stearate (557-04-0) are separate substances. The magnesium salts carry a separate code as a food additive, E 470b.
Potassium oleate, potassium palmitate and potassium stearate are also separate salts. Since E 470a is a common code covering them, a purchase request should state which fatty acid composition the product has and which CAS number applies.
Products in paste form are a different case. The potassium stearate pastes used in cake gel production consist of glycerol and potassium salts of fatty acids. These pastes must not be sold with the same identity data as solid Potassium Stearate; whether solid or paste is wanted should be stated separately in the request.
CAS NO, EC / EINECS NO AND CHEMICAL IDENTIFICATION OF POTASSIUM STEARATE
Product name: Potassium Stearate / Potasyum Stearat
Chemical name: Potassium octadecanoate
INCI name: Potassium Stearate
Food additive number: E 470a (sodium, potassium and calcium salts of fatty acids); Codex INS 470(i)
CAS No: 593-29-3
EC / EINECS No: 209-786-1
Molecular formula: C₁₈H₃₅KO₂; CH₃(CH₂)₁₆COOK
Molecular weight: 322.57 g/mol
Chemical class: Alkali metal salt of a long-chain saturated fatty acid; potassium soap
Main functions: Emulsifier, stabilizer, anticaking agent, binder, release agent and lubricant; cleansing surfactant; pH-adjusting and water-retaining effect
In Europe, the substance has been evaluated as a food additive in the group of fatty acid salts under the code E 470a. It also appears in the cosmetic ingredient database under its INCI name. The UNII code is 17V812XK50.
In REACH Annex V, fatty acids of natural origin in the range C6–C24 and their potassium, sodium, calcium and magnesium salts are counted among the substances exempt from the registration obligation. Whether this exemption applies to a specific product should be confirmed with the supplier.
The existence of an INCI name does not mean that the product can be used in cosmetics, and the existence of a food additive number does not mean that every grade can be used in food. For use in food, the product must meet the E 470a specification and comply with the food legislation of the relevant country.
The CAS number is necessary to match the product with the right substance, but it does not show quality on its own. For this reason, in purchases for food purposes, the quality grade, fatty acid composition and documents should be requested together with the CAS number.
CHEMICAL STRUCTURE AND MOLECULAR PROPERTIES OF POTASSIUM STEARATE
Potassium Stearate is an ionic salt. Its structure contains a potassium cation (K⁺) and an 18-carbon stearate anion (CH₃(CH₂)₁₆COO⁻). The anion has a polar carboxylate group at one end and a 17-carbon, unbranched and saturated nonpolar hydrocarbon chain at the other.
There is no double bond in the chain. For this reason the molecule has the form of a straight rod, and in the solid state the chains line up parallel to one another and pack tightly. The saturated structure makes the product more resistant to oxidation than unsaturated soaps such as oleate. A low iodine value is therefore required in food specifications.
The carbon-carbon and carbon-hydrogen bonds are covalent and nonpolar. In the carboxylate group, the negative charge is delocalized between the two oxygens; this group can form hydrogen bonds with water. The bond between potassium and the carboxylate is ionic. This two-sided nature of the structure is the basis of the substance being surface active.
Stearic acid is a weak acid with a pKa of about 4.5. For this reason, Potassium Stearate behaves as a salt formed from a strong base and a weak acid; it is partly hydrolyzed in water and gives the solution an alkaline character. Potassium soaps are hydrolyzed more than comparable sodium soaps.
In an acidic medium the stearate anion is protonated and water-insoluble stearic acid is released. For this reason, when the pH is lowered, the solution becomes cloudy or precipitates. In food systems in which Potassium Stearate is used, the pH value is therefore controlled carefully so that the function is maintained.
Divalent cations such as calcium and magnesium form insoluble salts with the stearate anion. In hard water this leads to a precipitate similar to lime soap. This is also the reason why water hardness affects the gelling temperature in cake gel production.
The most important structural property related to solubility is chain length. Potassium soaps dissolve very sharply at a certain temperature; this temperature is known as the Krafft temperature. Saturated long-chain soaps have low solubility at room temperature and dissolve well when heated.
In aqueous solution, as the concentration rises, stearate anions exceed the critical micelle concentration and form micelles with the nonpolar tails inside and the carboxylate heads outside. These structures dissolve oil, surround oil droplets and provide the cleansing and emulsifying effect of the soap.
Thermal stability is high. According to safety data sheets, the solid product begins to decompose above about 200 °C. The decomposition products are reported as carbon dioxide, carbon monoxide and potassium oxide. In practical use, the limiting factors are pH, water hardness and moisture rather than temperature.
The factors that determine participation in reactions through structure can be summarized under four headings. The first is the length and saturation of the chain. The second is the acid-base behavior of the carboxylate group. The third is the presence of divalent ions in the solution. The fourth is the temperature of the medium and the amount of water.
PHYSICAL AND CHEMICAL PROPERTIES OF POTASSIUM STEARATE
General technical specifications:
Values may vary by manufacturer, grade and measurement method; the information below is for general information purposes and does not replace manufacturer-specific TDS and SDS documents.
Physical appearance: White or creamy white, fine powder, flakes or semi-solid with a slightly fatty odor and a greasy feel to the touch
Chemical character: Potassium salt of a saturated long-chain fatty acid; anionic surfactant; its aqueous solution is alkaline because it is the salt of a weak acid
Molecular formula: C₁₈H₃₅KO₂
Molecular weight: 322.57 g/mol
CAS No: 593-29-3
EC / EINECS No: 209-786-1
Purity (assay): The EU specification requires at least 95 percent fatty acid salt on the basis of the product dried at 105 °C. Supplier specifications give at least 98 percent on a dry basis, and at least 97.5 percent for one laboratory grade. These are specification limits; typical values depend on the manufacturer
Potassium content (as K₂O): 13–21.5 percent in the EU specification. The theoretical value for pure potassium stearate is about 14.6 percent
Free fatty acids: At most 3 percent as oleic acid in the EU and JECFA specifications; the typical value of one manufacturer is about 0.7 percent
Free alkali: At most 0.1 percent as NaOH in the EU specification; supplier specifications give at most 0.2 percent or 1 percent for free KOH
Unsaponifiable matter: At most 2 percent in the EU specification
Alcohol-insoluble matter: At most 0.2 percent in the EU specification for sodium and potassium salts
Fatty acid composition: In one supplier specification, at least 40 percent of the fatty acids is stearic acid, and the total of stearic and palmitic acid is at least 90 percent. The composition varies with the raw material
Iodine value: At most 3 for one supplier and at most 4 g I₂/100 g for one laboratory grade; a low value indicates a saturated structure
Density: About 1.12 g/cm³ for the solid; one safety data sheet gives a relative density of 0.95–1.15
Solubility in water: Slightly soluble in cold water and dissolves well in hot water; soluble in ethanol. Insoluble in ether, chloroform and carbon disulfide. Some databases give the water solubility as “insoluble”; this relates to cold water conditions
pH (aqueous solution): Alkaline; given as 10–11 by one manufacturer. It should not be taken as a single value without stating the concentration and temperature
Decomposition: According to safety data sheets, the solid product decomposes above about 200 °C; the decomposition products are carbon dioxide, carbon monoxide and potassium oxide. As a fine dust it can form a combustible dust-air mixture
Moisture: The EU specification is defined on a dry basis and sets no limit for water. Supplier specifications give a loss on drying of at most 5 percent or 2 percent, and one safety data sheet gives below 6 percent
Heavy metals (Pb, Cu, etc.): In the EU specification, arsenic at most 3, lead 2, mercury 1 and cadmium 1 mg/kg. One supplier gives heavy metals (as Pb) at most 10 mg/kg
Reactivity: Stable under normal conditions. Incompatible with strong oxidizers, peroxides and strong mineral acids. With acid, stearic acid is released; with calcium and magnesium ions, an insoluble soap is formed
Brief Description of Physical Properties
Potassium Stearate is stable for a long time in dry, cool and closed packaging. Some values in data sheets may look inconsistent at first sight; most of the differences come from the fatty acid composition, the grade, the measurement condition or the source of the document.
The purity value can be expressed in two different ways. Some documents give the total fatty acid salt, others give the amount of fatty acid separated from the salt by acid. In a pure stearic acid salt, the fatty acid proportion is theoretically about 88 percent; a fatty acid content of 83 percent therefore corresponds to a salt of about 94 percent.
Solubility is very sensitive to temperature. Potassium soaps dissolve sharply at a certain temperature, and for this reason, in food processes the aqueous phase is mostly prepared by heating to the range of 70–95 °C. Dispersion in cold water or a cloudy suspension is not a defect but a result of this property.
The boiling point of 359 °C seen in databases is a calculated value and does not reflect a real boiling behavior of the salt. The melting point also varies with grade; in safety data sheets it is given as above 200 °C, and the substance may begin to decompose before it melts.
The pH and free alkali values depend on the solution concentration, the proportion of free fatty acid and the hardness of the water. Since the fatty acid composition, moisture and metal limits reflect production quality, they should always be checked from the manufacturer’s TDS and COA documents.
HOW DOES POTASSIUM STEARATE WORK AT THE MOLECULAR LEVEL?
When Potassium Stearate dissolves in water, it separates into K⁺ ions and stearate anions. The carboxylate head of the stearate anion likes water, while its 17-carbon chain avoids water. This two-sided structure directs the anions to the water-oil interface and lowers surface tension.
The emulsifying effect arises from this orientation. The nonpolar tails of the stearate anions attached to the surface of an oil droplet face the oil, and their charged heads face the water. The negatively charged layer formed around the droplets prevents them from merging. In this way the oil-water mixture becomes more stable.
At sufficient concentration, stearate anions form micelles. The nonpolar chains gather inside the micelles; this structure dissolves oil and dirt and keeps them in the aqueous phase. In potassium soaps this behavior starts suddenly when the temperature passes a certain threshold; below the threshold the substance remains as crystals or a dispersed solid.
In cake gel systems the effect is more complex. Monoglycerides and similar emulsifiers in the oil phase form an α-crystalline gel structure with the aqueous phase. Potassium Stearate, which is present in the aqueous phase, contributes to pH, water retention and gelling behavior according to suppliers. The gelling temperature falls as calcium in the water increases.
The reason for this is divalent cations. Calcium binds the stearate anions and turns them into insoluble calcium stearate; the amount of functional soap in the water decreases and the formation condition of the gel changes. The same mechanism is also the reason why soap foam weakens in hard water.
The anticaking effect is based on a different mechanism. The stearate layer settled on fine powder particles makes the surface hydrophobic and reduces the sticking formed by moisture bridges. The friction of particles against one another also decreases; the powder becomes more free-flowing.
The lubricating and release effect is based on the same surface phenomenon. The chains form an oriented film on the surface; the film lowers the friction between the tablet and the die or between two surfaces. For this reason the product is used in tablet compression and mold release.
The alkaline reaction is also important. The stearate anion reacts slightly with water and forms hydroxide ions and free fatty acid. This equilibrium raises the pH of the solution. When the pH falls, the equilibrium shifts toward free stearic acid and the solution becomes cloudy.
In the stomach and intestine, Potassium Stearate is assumed to dissociate into fatty acid carboxylate and potassium ions. Stearic acid and palmitic acid are fatty acids that already occur naturally in foods. For this reason, evaluations are made on the intake of fatty acids and potassium rather than on the salt itself.
In synthetic rubber production, stearate anions surround monomer droplets and support particle formation in emulsion polymerization. The same surface effect is also the basis of the cleansing and foam-forming function in cosmetics and cleaning products.
IN WHICH SECTORS IS POTASSIUM STEARATE USED?
Potassium Stearate takes part in more than one sector because of its surface-active and release properties. Its use in the food field is the most prominent; besides this, it is also used in cosmetics, soap, plastics, rubber and pharmaceuticals. The main sectors and functions are given below.
Bakery and pastry
It is used in the aqueous phase of cake gel emulsifier systems. It contributes to the stability of the gel, which helps support the aeration, volume and pore structure of the batter. Use in this field is one of the most common examples of the product in food.
Margarine, spreads and fat emulsions
It is used as a co-emulsifier in margarine, low-fat spreads and similar water-in-oil emulsions. It reduces phase separation and contributes to consistency stability.
Dairy alternatives and non-dairy creams
It takes part as a co-emulsifier in products such as imitation cream, non-dairy coffee creamer and vegetable whipping cream. It supports the stability of fat droplets and the structure of the foam.
Sauces and salad dressings
It is used in sauces and salad dressings to reduce oil-water separation, maintain consistency and balance surface tension. The effect depends on the pH and salt content of the product.
Powdered foods and spice blends
As an anticaking agent, it maintains flowability in instant soup, spice, seasoning and supplement powders. Its use in dried spices is permitted in the EU. In food powders, the sticking caused by moisture absorption is reduced.
Tablet products and confectionery
Its use in tablet table-top sweeteners is permitted in the EU. It is used as a lubricant and release agent in tablet compression, and as a binder and softener in the production of confectionery and chewing gum base.
Cosmetics, soap and personal care
It takes part as a cleansing agent and emulsifier in liquid and solid soaps, shampoos, shaving foams and bath products. For cosmetic use, a grade that complies with cosmetic regulations, rather than food grade, is sought.
Pharmaceuticals and food supplements
It is seen to be offered as a lubricant and flow regulator in tablet and capsule production. Use as a pharmaceutical excipient depends on the relevant pharmacopoeia and legislation; in food supplements, the E 470a conditions apply.
Plastics and rubber
It is used as a lubricant and stabilizer in polyolefin, PVC and acrylic rubber production. It takes part as an emulsifier in the emulsion polymerization of butadiene and similar monomers in synthetic rubber production.
Lubricants, wax and textiles
Potassium soaps are used to thicken natural and synthetic oils and to increase the melting point and flexibility of wax and paraffin. It also takes part as a base material in the preparation of textile softeners.
Edible fat industry
Potassium soaps used as a catalyst in the production of mono- and diglycerides make the resulting glyceride esters self-emulsifying. Details depend on the process and the manufacturer.
For each field, the quality of the product, its documents and its compliance with the relevant legislation should be evaluated separately.
IS POTASSIUM STEARATE USED IN COSMETIC, FOOD AND PHARMACEUTICAL APPLICATIONS?
Cosmetic applications
Yes. Potassium Stearate appears in the cosmetic ingredient database with the functions of cleansing agent, surfactant cleansing agent and surfactant emulsifying agent. It is used in soaps, shampoos, shaving foams and cleansing products; it is a relatively little-used ingredient in cosmetics.
The Cosmetic Ingredient Review panel found fatty acids and their salts safe under current conditions of use, as long as they are formulated to be non-irritating and non-sensitizing. A safety assessment must be carried out separately for each product.
For a food grade product to be used in cosmetics, the cosmetic legislation and quality expectations must also be met. The two fields do not automatically replace each other.
Food applications
Yes. Potassium Stearate is a member of the group of sodium, potassium and calcium salts of fatty acids known in food as E 470a, and it is used as an emulsifier, stabilizer and anticaking agent. It is an additive added directly to food.
It has been evaluated as an additive in the EU. The European Food Safety Authority concluded in 2018 that there was no safety concern at the reported use levels and that there was no need to set a numerical acceptable daily intake.
JECFA has also accepted the acceptable daily intake for these salts as “not specified”. This statement means that use at the level technologically needed in food does not pose a health problem.
In Europe, the conditions of use are set in the additives regulation; in general, the principle of use at the level technologically needed, without a set quantity limit, applies. Use is restricted in some food categories, so the current text should be checked according to the product category.
In the USA, these salts are among the additives permitted as binders, emulsifiers and anticaking agents within the framework of good manufacturing practice. On the label of the additive, the name of the salt and the words “food grade” must appear.
For food grade, the EU specification requires at least 95 percent purity, at most 3 percent free fatty acids, at most 0.1 percent free alkali and certain heavy metal limits. If it is not known that the product will be used in food, these limits may not be met.
In Türkiye, food additives are regulated by the Turkish Food Codex Regulation on Food Additives and the regulation on the specifications of these substances. The conditions of use and the specification for E 470a should be verified separately from the current legislation.
EFSA has also recommended that trans fatty acid limits be added to the specification and that it be made clear that the fatty acids come only from edible fats and oils. For this reason, it is appropriate for buyers to ask for information on the fatty acid source and hydrogenation status.
Pharmaceutical applications
No. Potassium Stearate is not a pharmaceutical active ingredient. Some suppliers offer the product as a lubricant and flow regulator in tablet and capsule production; however, its use as a pharmaceutical excipient requires compliance with the relevant pharmacopoeia and legislation.
In the pharmaceutical field, magnesium stearate is the more widely known option for this function. If the use of Potassium Stearate in a pharmaceutical formulation is being considered, the suitable grade, documents and limits of use should be verified separately.
The use of a chemical in one sector does not mean that it can be used in other sectors as well.
INDUSTRIAL APPLICATIONS OF POTASSIUM STEARATE
The industrial use of Potassium Stearate rests on carrying, in a single molecule, a part that likes water and a part that likes oil. The headings below describe the function of the product, the reasons for choosing it and its limits, application by application. Food applications are placed first.
Cake gel and cake emulsifier systems
Cake gel is a ready-made emulsifier system that creates evenly distributed and stable air bubbles in cake batter. Monoglycerides and polyglycerol esters in the oil phase combine with Potassium Stearate in the aqueous phase to form the gel. Potassium stearate pastes consist of glycerol and potassium salts of fatty acids.
Suppliers state that this system contributes to the aeration of the batter, cake volume, a fine and even crumb structure and softness. The limitation is sensitivity to water hardness: as calcium in the water increases, the gelling temperature falls. Alternatives are gels based only on monoglycerides or ready-made powder emulsifier blends.
Margarine, spreads and fat emulsions
In margarine and low-fat spreads, Potassium Stearate is used as an aid to the main emulsifiers. Its function is to keep the interface between the water and fat phases stable and to reduce the deterioration of consistency over time.
Since the product is alkaline, it can raise the pH of the final product; for this reason the buffer system and flavor balance are evaluated together. Alternatives are monoglycerides, lecithin and polyglycerol esters. The amount used is determined according to the formulation and the regulations for the product category.
Non-dairy creams and dairy alternatives
It takes part as a co-emulsifier in imitation cream, non-dairy coffee creamer and vegetable whipping creams. It surrounds fat droplets, reduces the breakdown of the emulsion and supports the structure of the foam formed during whipping.
Use in acidic products is limited, because at low pH the stearate turns into free stearic acid and loses its function. For this reason use is more suitable in systems with a neutral or slightly alkaline pH. Alternatives are sodium stearoyl lactylate, polysorbates and sucrose esters.
Sauces and salad dressings
In sauces it can be used to reduce oil-water separation and balance surface tension. Suppliers particularly emphasize the thickening and emulsion stability function.
Since the pH of sauces is mostly acidic, the effect of Potassium Stearate may remain limited. The ratio of acid and salt is the main factor that determines applicability. For this reason, small-scale stability trials are recommended before use in a sauce.
Powdered foods and prevention of caking
In instant soup, spice, seasoning and supplement powders, it is used as an anticaking agent to reduce sticking caused by moisture. The fine powder coats the particle surface and maintains flowability.
The effect depends on the dose and the moisture state of the blend. In the EU, permission for use varies by category; for example, it is permitted in dried spices. Alternatives are silicon dioxide, calcium stearate and magnesium stearate.
Tablet products, table-top sweeteners and food supplements
In tablet compression, Potassium Stearate acts as a lubricant and release agent and reduces the sticking of the tablet to the die. In the EU, its use in tablet table-top sweeteners is permitted.
Excessive mixing can make the surface too hydrophobic; this can prolong the disintegration time of the tablet. For this reason the lubricant is added last and with brief mixing. Alternatives are magnesium stearate, stearic acid and sodium stearyl fumarate.
Confectionery and chewing gum base
It is reported to be used in chewing gum base as a binder, emulsifier, anticaking agent and softener. In confectionery production it may be preferred for its release effect on mold and belt surfaces.
Use in this field may fall under different regulations depending on the country. The additive list and purity criteria of the relevant country must be checked separately for chewing gum base and confectionery products. Alternatives are monoglycerides and glyceride esters.
Soap, cosmetics and cleaning products
It takes part as a cleansing agent and emulsifier in liquid and solid soaps, shampoos and shaving foams. Potassium soaps give a softer and more easily soluble structure than sodium soaps.
In hard water, an insoluble calcium soap can form; this reduces foam and cleaning power. In acidic formulas, on the other hand, stearic acid separates. Alternatives are sodium stearate, sulfate-based surfactants and glycoside-type surfactants.
Plastics and synthetic rubber
It is used as a lubricant and stabilizer in polyolefin, PVC and acrylic rubber production. It takes part as an emulsifier in synthetic rubber production in the emulsion polymerization of butadiene, styrene, acrylonitrile and acrylic esters.
Food grade is not sought in these fields; a technical grade is sufficient. Zinc, calcium and magnesium stearates are more common in plastics. Potassium Stearate, on the other hand, stands out in emulsion systems because it can be dispersed in water.
Mono- and diglyceride production
Potassium soaps can be used as a catalyst in the production of fatty acid glyceride esters. It is also reported that they help the resulting glyceride esters to form emulsions spontaneously.
The details of this use depend on the manufacturer and the process. The final food emulsifier must meet the relevant specifications with respect to the catalyst residues used.
CONSIDERATIONS IN THE USE OF POTASSIUM STEARATE
Potassium Stearate is a widely accepted additive in the food field with low acute toxicity. Even so, the product must be selected in the right grade and used under the right conditions. The main points to keep in mind during use are as follows:
• A grade suitable for food should be selected. Technical, cosmetic or laboratory grades carrying the same CAS number may not be suitable for use in food. Compliance with the E 470a specification should be documented
• The source of the fatty acid should be known. Sources such as palm, soy and animal fat matter for halal, kosher, vegetarian or allergen declarations. The source document should be requested from the supplier
• Use should comply with the legislation of the target country. Permitted food categories, quantity limits and labeling rules may differ in the EU, the USA and Türkiye. The current legislation should be checked
• The pH value should be controlled. In an acidic medium the stearate turns into free stearic acid and loses its function. Since the product is alkaline, it can also raise the pH of the final product
• Water hardness should be taken into account. Calcium and magnesium ions form an insoluble soap; the gelling temperature and emulsion stability can change as a result. If necessary, softened or demineralized water is used
• The dissolving temperature should be reached. Potassium soaps do not dissolve well in cold water; in processes, the aqueous phase is generally heated to the range of 70–95 °C. Excessive foaming and air entry should be monitored
• It should be protected from moisture. The product can cake with moisture and form deposits as a fine dust. An opened package should be closed immediately, and the remaining product should not be returned to the original package
• Dust formation should be prevented. Fine dust can form a combustible dust-air mixture. Ignition sources should be avoided, and grounding and ventilation should be provided
• It should be kept away from incompatible materials. There should be no contact with strong oxidizers, peroxides and strong mineral acids
• Cross-contamination should be avoided. In food production, equipment, weighing containers and scoops should be clean, dry and used only for food purposes
• Protective equipment should be used. Because of dust, eye and upper respiratory tract irritation may occur; protective goggles, gloves and, when necessary, a dust mask should be used
• The quantity should be determined according to good manufacturing practice. The additive should be used at the lowest level necessary for the technological purpose and declared on the label as E 470a
This information is for general information purposes and does not replace product-specific SDS and TDS documents.
INITIAL FORMULATION APPROACHES FOR POTASSIUM STEARATE
The examples below are starting approaches prepared to show how Potassium Stearate can be evaluated in food formulations. They are not validated commercial recipes, production instructions or final formulas that comply with regulations.
The ratios given are example starting levels for laboratory preliminary trials, and the total of each formula is 100%. Every ingredient to be used in food must be of food grade, and the conditions of use of E 470a must be verified for the target country.
The fatty acid composition of the product used, its free alkali content, the hardness of the water, pH and temperature change the result. In every application, technical evaluation, food safety and relevant regulatory checks should be carried out, and the ratios should be reviewed by experts.
EXAMPLE 1: EVALUATION OF THE USE OF POTASSIUM STEARATE IN A CAKE GEL EMULSIFIER SYSTEM
Purpose: To examine the effect of Potassium Stearate in the aqueous phase of a cake gel emulsifier system on gel stability, gelling temperature, batter aeration and cake properties.
Starting approach:
Water: approx. 65%
Distilled monoglyceride and polyglycerol ester blend: approx. 30%
Potassium Stearate (paste or powder): approx. 5%
Application approach:
• The aqueous phase is prepared and the hardness of the water is recorded; it is known that water with a high calcium content lowers the gelling temperature.
• The water phase is heated to about 95 °C and the Potassium Stearate is dissolved.
• The heated aqueous phase is added into the oil phase from below the surface; in this way air is not entrained.
• Mixing is done with a high-speed mixer; after thorough mixing, the speed is lowered and the air bubbles are left to escape.
• The temperature is cooled in a controlled way so that it does not fall below the gelling temperature; when the gel becomes clear, it is packaged.
• The consistency, gelling temperature and stability over time of the gel are monitored; the gel is added to the cake batter.
• Batter density, cake specific volume, pore structure and crumb softness are measured and the results are compared.
• Heat-resistant gloves and protective goggles are used when working with the hot mixture; all ingredients must be of food grade.
EXAMPLE 2: EVALUATION OF THE ANTICAKING LEVEL OF POTASSIUM STEARATE IN DRY SPICE AND SEASONING BLENDS
Purpose: To examine the effect of Potassium Stearate on caking under moisture, flowability and particle structure in a powdered spice and seasoning blend.
Starting approach:
Dried spice and seasoning blend: approx. 99.5%
Potassium Stearate: approx. 0.5%
Application approach:
• The blend is prepared in clean and dry equipment; Potassium Stearate is added as a fine powder and pre-sieved.
• Mixing is done for a time that ensures homogeneous distribution but does not grind the product.
• The moisture content of the blend is measured; the tendency to cake is evaluated by keeping it for a certain period in a humid environment.
• Flowability, sieve residue and bulk density are measured and compared with the blend without additive.
• Taste, appearance and dissolving behavior are checked sensorially.
• Use should be made only in the food categories permitted by the relevant country; in the EU, use is permitted in dried spices.
• Ventilation and grounding are provided against dust formation and combustible dust risk; a mask and goggles are used.
EXAMPLE 3: EVALUATION OF THE LUBRICANT LEVEL OF POTASSIUM STEARATE IN A TABLE-TOP SWEETENER TABLET
Purpose: To examine the effect of Potassium Stearate on compression, ejection from the die, tablet hardness and disintegration time in a tablet table-top sweetener.
Starting approach:
Sweetener and filler granules: approx. 99.25%
Potassium Stearate: approx. 0.75%
Application approach:
• The granules are prepared in a dry environment; Potassium Stearate is sieved and added at the end of the mixing.
• The mixing time with the lubricant is kept short; excessive mixing can make the surface hydrophobic and delay disintegration.
• Tablets are pressed at different compression forces and the ejection force from the die is measured.
• Tablet hardness, friability loss, weight variation and disintegration time in water are compared.
• Sticking to the die or punch is observed; the trial without lubricant is taken as the reference.
• Use must comply with the rules of the relevant country for tablet table-top sweeteners; in the EU, use is permitted for this category.
• A dust mask and goggles are used during the work, and dust accumulation is prevented.
SIMILAR PRODUCTS AND ALTERNATIVES TO POTASSIUM STEARATE
An alternative to Potassium Stearate does not simply mean choosing another fatty acid salt. When choosing an alternative in food, function, pH range, solubility, flavor effect, regulatory permission, label declaration and cost should be evaluated together.
POTASSIUM STEARATE AND SODIUM STEARATE
Sodium stearate is the sodium salt of the same fatty acid and is in the same group under E 470a. Compared with the potassium salt it is harder, dissolves less easily in water and gives a hard soap. Potassium Stearate, on the other hand, provides a softer structure that disperses more easily in water.
Sodium stearate can be a disadvantage in products where sodium intake is to be limited. The potassium salt fits the goal of reducing sodium through its potassium content. The choice is made according to the dissolving rate and the salt profile of the product.
POTASSIUM STEARATE AND CALCIUM STEARATE
Calcium stearate does not dissolve in water and is used mostly as an anticaking agent, release agent and lubricant. It is common in powder and tablet production. Its emulsifying power is very limited compared with Potassium Stearate.
The calcium salt is not suitable in emulsifier systems that must work in the aqueous phase. In dry blends, on the other hand, its insolubility in water can be an advantage in moisture-absorbing blends. Food use categories and permissions must be checked separately.
POTASSIUM STEARATE AND MAGNESIUM STEARATE
Magnesium stearate is registered in food as E 470b and is very common as a tablet lubricant. It is insoluble in water, reduces the sticking of the tablet to the die, and is preferred more often than Potassium Stearate for this task.
Its effect as an emulsifier is limited. For this reason it does not replace Potassium Stearate in aqueous systems. In dry applications such as tablets, it can be a direct alternative.
POTASSIUM STEARATE AND MONO- AND DIGLYCERIDES
Mono- and diglycerides of fatty acids (E 471) are the most widespread group of emulsifiers in food. They are used as the main emulsifier in dough, margarine, cream and cake gel. They lower the interface between water and oil strongly.
Potassium Stearate is mostly used together with these emulsifiers rather than instead of them. In cake gel in particular, it contributes to the stability of the aqueous phase. Systems that use only monoglycerides are simpler, but the pH balance may be more limited.
POTASSIUM STEARATE AND POLYGLYCEROL ESTERS
Polyglycerol esters of fatty acids (E 475) are successful in air retention and foam stability. They are used in cake, biscuits and whipping creams. They are less affected by pH than alkaline salts.
In acidic systems where an alkaline salt such as Potassium Stearate cannot be used, these esters can be more suitable. Their cost and effect vary with the application.
POTASSIUM STEARATE AND STEAROYL LACTYLATES
Sodium and calcium stearoyl lactylate (E 481, E 482) are used especially in bread and dough products as dough strengtheners and softeners. They interact with starch and gluten and help the bread crumb stay soft.
Potassium Stearate, on the other hand, takes part more in emulsion and gel systems. The two do not replace each other in every application; stearoyl lactylates are more common in bread and dough, and the stearate salt in cake gel.
POTASSIUM STEARATE AND LECITHIN
Lecithin (E 322) is a natural emulsifier with a phospholipid structure. It is used in margarine, chocolate, cake and powder products. It offers the advantage of natural origin on the label. It can be of soy or sunflower origin; for soy-derived products an allergen declaration is required.
Since it is less affected by acid and salt, it works over a wide pH range. Its color and odor may carry over into the product. Because it does not have an alkaline soap character, its gel-forming power differs from that of Potassium Stearate.
POTASSIUM STEARATE AND POLYSORBATES, SUCROSE ESTERS
Polysorbates (E 432–436) and sucrose esters (E 473) are emulsifiers with a predominantly hydrophilic character. They are effective in oil-in-water emulsions and foamed products rather than in water-in-oil systems. They work at low doses and are more stable against pH changes.
Unlike Potassium Stearate, they are not fatty acid soaps; they do not precipitate in hard water. However, their costs and limits of use are different, and the taste of polysorbates can be noticeable in some products.
POTASSIUM STEARATE AND SILICON DIOXIDE
Silicon dioxide (E 551) is one of the most common anticaking agents in powdered foods. It maintains flowability by absorbing moisture and is effective at very low doses. It is chemically inert.
Potassium Stearate works by coating the particle surface and at the same time carries an emulsifier or lubricant function. In very oily and moist powders silicon dioxide can be more effective; the stearate salt may be preferred in blends where a fat-like texture is needed.
POTASSIUM STEARATE AND OTHER POTASSIUM SOAPS
Other potassium fatty acid salts such as potassium oleate and potassium palmitate show similar surface-active behavior. Oleate, with its unsaturated fatty acid, is more liquid and dissolves more easily, while palmitate has a structure close to stearate.
As food additives, these salts are evaluated in the same E 470a group. Since commercial Potassium Stearate is often a mixture of stearate and palmitate, the difference most often stems from the fatty acid composition.
QUALITY CONTROL AND PURCHASING CRITERIA FOR POTASSIUM STEARATE
Even when sold under the same name, the fatty acid composition, free alkali, moisture and impurity level of Potassium Stearate differ according to the manufacturer and grade. For food use, compliance of the product with the E 470a specification should be confirmed with a document.
The main parameters that can be evaluated in the quality control and purchasing process:
• Purity (assay): At least 95 percent is expected on the dried substance in the EU specification. Some suppliers give at least 97.5 percent or 98 percent on dry matter
• Potassium content: In the EU specification, K₂O is in the range of 13–21.5 percent. The theoretical value for pure stearate is about 14.6 percent
• Free fatty acids: Given as at most 3 percent in the EU and JECFA specifications. A high value can indicate bad taste, odor and low emulsifying performance
• Free alkali: At most 0.1 percent as sodium hydroxide in the EU specification; a limit of up to 0.2 percent for free KOH is seen at some suppliers. Excess alkali increases the irritant power and pH of the product
• Unsaponifiable matter: Given as at most 2 percent. It shows the purity of the fat used as the raw material
• Alcohol-insoluble matter: At most 0.2 percent for sodium and potassium salts
• Fatty acid composition: The proportion of stearic and palmitic acid may be stated by the supplier with values such as at least 90 percent. This proportion determines the melting and dissolving behavior of the product
• Iodine value: Shows the amount of unsaturated fatty acids. Some suppliers give at most 3–4; a low value is important for color and oxidation stability
• Moisture: The EU specification has no limit for water; suppliers give values in the range of at most 2–6 percent for loss on drying. Moisture affects caking and shelf life
• Heavy metals and toxic elements: In the EU specification, arsenic at most 3, lead 2, mercury 1 and cadmium 1 mg/kg. Some suppliers give a limit of up to 10 mg/kg for total heavy metals as lead
• Appearance and odor: It should be a white or creamy white powder, flakes or semi-solid. A yellow color, rancid odor or foreign matter is a quality problem
• Fatty acid source: Vegetable or animal origin, sources such as palm and soy, halal and kosher status and the allergen declaration should be documented
• Documents: A batch-specific certificate of analysis, current SDS, TDS, food grade declaration, food safety certificate and regulatory compliance information should be requested
• Packaging and batch: A 25 kg bag or drum is seen at one supplier, and 25 or 50 kg polyethylene-lined bags at another. Batch number, production date and expiry date should be checked
The manufacturer’s typical values must be distinguished from binding product specifications. Typical values are generally for information; the specification in the purchase contract and the batch results in the certificate of analysis should be taken as the basis.
STORAGE AND TRANSPORT OF POTASSIUM STEARATE
Potassium Stearate is stable for a long time in dry and closed packaging. Since it is a food additive, hygiene and cross-contamination during storage are also important.
• Temperature and place: It is stored in a cool and dry place, away from heat sources and direct sunlight. High temperature adversely affects the caking and odor of the product
• Moisture: The package should be kept tightly closed. The product absorbs moisture; a moistened product cakes and its dissolving behavior changes
• Packaging: It should be stored in its original packaging with the label intact. The residual product in an opened package should not be returned to the original package. At one supplier, a 25 kg drum or a polyethylene bag together with a foil bag is used
• Storage environment: A clean, odor-free area reserved for food additives and subject to pest control is preferred. It should not be stored together with strongly smelling and chemical substances
• Incompatible materials: It should be kept separate from strong oxidizers, peroxides and strong mineral acids. Contact with acids forms stearic acid and spoils the function of the product
• Dust and fire: Fine dust can form a combustible dust-air mixture. Ignition sources should be avoided and dust accumulation should be prevented
• Stacking: Pallets should be stacked above the floor and apart from the wall, and care should be taken that packages on the lower tiers are not crushed
• Shelf life: Two years under suitable conditions is given at one supplier. A product kept for a long time can be retested for free fatty acids, moisture and odor before use
• Transport: In safety data sheets the product is not classified as dangerous goods under ADR, IMDG, IATA and DOT. No UN number is given
• Transport classification: This may depend on the product form, composition and document date. Before shipment, the supplier’s current SDS and the applicable transport legislation should be taken as the basis
• During transport: Packaging integrity should be maintained, the product should be protected from moisture and heat, and it should not be loaded in the same vehicle as non-food chemicals in a way that creates a contact risk
SAFETY INFORMATION ON POTASSIUM STEARATE
Potassium Stearate has been evaluated as a food additive and is a substance of low toxicity. Classification differs in the safety data sheets of different manufacturers; in most documents the product is not classified as hazardous, while in some skin and eye irritation is reported.
The information below is for general information purposes and does not replace the manufacturer-specific safety data sheet. The SDS of each supplier should be taken into account.
Main safety topics:
• Hazard classes: In most SDSs the product is not classified. In some documents skin irritation (H315) and serious eye irritation (H319) are reported. Classification may vary depending on the free alkali content and the composition of the product
• Classification differences: Some documents include an aquatic toxicity statement, but this information may have been copied from other products. For correct classification, a current SDS consistent with the batch should be requested from the supplier
• Food safety: In the EU, the European Food Safety Authority found no safety concern at the reported use levels; JECFA accepted the acceptable daily intake as “not specified”. These assessments are based on the food grade product and permitted use
• Skin and eye contact: Dust or a concentrated solution can cause irritation because it is alkaline. In case of contact, it should be washed with plenty of water, the eyes should be rinsed for at least 15 minutes, and medical help should be obtained if irritation continues
• Inhalation: Fine dust can irritate the respiratory tract. The person should be moved to fresh air, and medical help should be obtained if symptoms continue
• Ingestion: If swallowed in an amount above the permitted use level in food, the mouth should be rinsed, and a health facility or poison control center (114 in Türkiye) should be contacted if discomfort continues
• Fire and reactivity: The product is not easily flammable, but fine dust can form a combustible dust-air mixture. In a fire, carbon dioxide, carbon monoxide and potassium oxide can be formed
• Occupational exposure: Some safety data sheets cite an ACGIH value of 10 mg/m³ for dust. Current limits in Türkiye should be checked separately
• Personal protective equipment: Protective goggles, gloves, suitable work clothing and, where dust is formed, a dust mask should be used
• Spills: It should be collected by sweeping or vacuuming without raising dust, in a closed container. Since it can create a slippery floor, the remainder should be cleaned with a damp cloth
• Environment: Fatty acid soaps are generally reported to be biodegradable. Even so, large quantities should not be released into waterways and sewers
• Waste: Residual product and contaminated packaging should be disposed of in accordance with local legislation. In food production, leftover product should not be returned to the food chain
WHAT SHOULD BE CONSIDERED WHEN BUYING POTASSIUM STEARATE?
To choose the right product, the identity of the product must first be determined clearly. Since Potassium Stearate can be confused with sodium, calcium and magnesium stearates, stearic acid and ready-made cake gel pastes, a request that only says “stearate” is insufficient.
In the request, the product name Potassium Stearate, the CAS number 593-29-3, the EC number 209-786-1 and, for food, E 470a should be stated together.
The main points to consider when buying:
• Food grade: Compliance of the product with the E 470a specification as a food additive should be confirmed in writing. Technical or cosmetic grades should not be used in food
• Intended use and regulation: The food category and the country in which the product will be used should be clarified, and the permissions and quantity limits should be verified
• Technical specifications: Purity, K₂O, free fatty acids, free alkali, unsaponifiable matter, moisture and heavy metal limits should be requested clearly
• Fatty acid composition and source: The stearate and palmitate ratio, vegetable or animal origin, and halal and kosher status should be asked
• Form: The requirement for powder, flakes or paste should be stated; the dissolving rate and dust formation depend on this choice
• Packaging and logistics: Net quantity, moisture-protective packaging, pallet arrangement and food-purpose labeling should be determined
• Batch consistency: The certificates of analysis and physical appearance of consecutive batches should be compared
• Shelf life: The production date and the remaining shelf life of the delivered product should be asked
• Documents: SDS, TDS, COA, food safety certificate and REACH status should be requested
• Supplier’s technical support: Support on dosage, dissolving and water hardness in applications such as cake gel and margarine should be evaluated
• Total cost of supply: Besides the unit price, the required dose, packaging, storage and quality control costs should be calculated together
In price comparison, not only the price per kilogram but also the purity, grade, level of documentation and supply security should be considered.
SUPPLY OF POTASSIUM STEARATE FROM ATAMAN KİMYA
Potassium Stearate is a multi-purpose product evaluated as a food emulsifier, anticaking agent, cosmetic and soap ingredient and industrial lubricant. A product page for Potassium Stearate is available on the ATAMAN KİMYA website.
On the current product page, the substance is presented mainly as an anionic surfactant for cosmetic and personal care uses. The page does not contain information on food grade, the E 470a specification or packaging.
For this reason, it is important for companies looking for food grade Potassium Stearate to confirm clearly with ATAMAN KİMYA, before ordering, the product’s compliance with the E 470a specification, its available quality grade and its documents.
Companies that want information about the supply of Potassium Stearate from ATAMAN KİMYA can share their areas of use and technical needs and request information on product suitability, current supply status, packaging options and a price quotation.
The current stock status, origin, quality grade, food grade declaration, purity and free alkali values, packaging and the regulatory conditions related to the intended use of the product should be confirmed with ATAMAN KİMYA before ordering.
Sharing the following information in a quotation request makes it easier to evaluate the right Potassium Stearate product:
• Sector of use and final application
• Food, cosmetic or technical grade requirement; E 470a request for food
• Target food category and country of use
• Required limits for purity, K₂O, free fatty acids and free alkali
• Requested form: powder, flakes or paste
• Fatty acid source and special requirements such as halal or kosher
• Estimated order quantity
• Requested packaging type
• Requested technical documents: SDS, TDS, COA and food safety documents
• TDS or COA information of the current product, if available
FREQUENTLY ASKED QUESTIONS ABOUT POTASSIUM STEARATE
What is Potassium Stearate?
Potassium Stearate is the potassium salt of stearic acid and has the formula C₁₈H₃₅KO₂. In food it is used as an emulsifier and anticaking agent under the code E 470a; it also takes part in fields such as cosmetics, soap and plastics.
What does Potassium Stearate mean?
The name stearate comes from stearic acid, a saturated fatty acid with 18 carbons. Potassium is the cation that forms the salt of this acid. The substance is also called potassium octadecanoate and stearic acid potassium salt.
What is the CAS number of Potassium Stearate?
The CAS number is 593-29-3. Mixture numbers such as 66072-07-9 can also be used for commercial fatty acid salts produced from a mixture of stearic acid and palmitic acid.
What is the EC / EINECS number of Potassium Stearate?
The EC number is 209-786-1. For salts of fatty acid mixtures, some suppliers give the number 266-119-7.
What is the chemical formula of Potassium Stearate?
The formula is C₁₈H₃₅KO₂ or CH₃(CH₂)₁₆COOK. The molecular weight is about 322.57 g/mol.
What does food grade Potassium Stearate mean?
Food grade means that the product meets the E 470a food additive specification and is produced under conditions suitable for food production. In the EU, purity of at least 95 percent, free fatty acids of at most 3 percent and heavy metal limits are defined.
What is the INCI name of Potassium Stearate?
The INCI name is Potassium Stearate. The existence of an INCI name does not mean that the product can be used without limit in every cosmetic product.
Is Potassium Stearate used in cosmetics?
Yes. It takes part as a cleansing agent and emulsifier in soaps, cleansers, shaving foams and creams. Fatty acids and their salts are considered safe in cosmetics when formulated to be non-irritating.
Does Potassium Stearate have an E code?
Yes. It is included under the code E 470a among the sodium, potassium and calcium salts of fatty acids. The Codex number is INS 470(i). The magnesium salts are E 470b.
What is the difference between Potassium Stearate and sodium stearate?
Both are stearic acid salts. The potassium salt is softer and disperses more easily in water, whereas the sodium salt is harder. The potassium salt does not increase sodium intake, whereas the sodium salt contains sodium.
What is Potassium Stearate used for?
In food it is used as an emulsifier, anticaking agent, release agent and co-thickener; in cosmetics as a cleansing agent; in industry as a lubricant and as an emulsifier in emulsion polymerization.
In which sectors is Potassium Stearate used?
It is used in the bakery and pastry, margarine and fat products, non-dairy cream, sauce, powdered food, tablet product, confectionery and chewing gum, cosmetic and soap, plastic, synthetic rubber and textile sectors.
How does Potassium Stearate perform its emulsifying function?
The oil-loving long-chain tail turns toward the oil phase and the water-loving carboxylate part toward the water phase. In this way it lowers the interfacial tension and keeps the emulsion stable by surrounding the droplets.
What is Potassium Stearate good for?
It prevents the separation of oil and water, reduces the caking of powders, prevents sticking on tablet and mold surfaces and supports air retention in cake gel.
How does Potassium Stearate work in cake gel and cake?
It contributes to the stability of the gel structure together with the monoglycerides in the oil phase. It supports the aeration of the batter and the distribution of air bubbles. The gelling temperature falls with water hardness.
Is Potassium Stearate soluble in water?
It is slightly soluble in cold water and soluble in hot water and ethanol. Potassium soaps dissolve suddenly at a certain temperature. It is insoluble in ether and chloroform. Its aqueous solution is alkaline.
How much Potassium Stearate is used in food?
In the EU it is, in general, an additive group without a quantity limit, that is, used at the lowest level required by technological need. Permission and conditions vary by category; the dose is determined according to the product, the formulation and the legislation. The current legislation should be checked.
Is Potassium Stearate a hazardous substance?
In most safety data sheets it is not classified as hazardous. Skin and eye irritation is reported in some documents. Its fine dust can form a combustible dust-air mixture. Even so, it should be used with protective goggles and gloves.
Why can Potassium Stearate cause skin and eye irritation?
Because its aqueous solution is alkaline and it is a surfactant, it can disturb the skin’s natural oil and protective layer. Excess free alkali increases the irritant power. Dry dust can also irritate the eye mechanically.
Is Potassium Stearate registered under REACH?
Fatty acids of natural origin in the range C6–C24 and their potassium, sodium, calcium and magnesium salts are exempt from the registration obligation under REACH Annex V. The registration or exemption status of a specific product should be confirmed with the supplier.
What is the physical appearance of Potassium Stearate?
It is a white or creamy white powder, flakes or semi-solid substance. It may have a slight fatty acid odor. It is also found in paste form.
What is the UN number of Potassium Stearate?
In safety data sheets, no UN number is given because the product is not classified as dangerous goods in road, sea and air transport. The supplier’s current SDS should be checked before shipment.
Why are free fatty acids, free alkali and heavy metals important in Potassium Stearate?
Free fatty acids spoil taste, odor and emulsifying performance. Free alkali increases irritation and pH. Arsenic, lead, mercury and cadmium are limited for food safety. For this reason the values should be verified from the COA.
What does the price of Potassium Stearate depend on?
The price varies according to purity, grade, fatty acid source, form, packaging, order quantity, origin, certification and logistics conditions. Food grade and halal or kosher certification can increase the cost.
Is there an alternative to Potassium Stearate?
Yes. Sodium, calcium and magnesium stearate, mono- and diglycerides, polyglycerol esters, stearoyl lactylates, lecithin, sucrose esters and silicon dioxide can be alternatives depending on the application. None of them is a direct substitute in every system.
How should Potassium Stearate be stored?
It should be stored in a cool, dry and ventilated place, in its closed original packaging, away from moisture, heat sources, strong oxidizers and acids. Products for food use should be kept separate from other chemicals.
Which documents should be requested when buying Potassium Stearate?
SDS, TDS and batch-specific COA are the basic documents. In addition, an E 470a compliance declaration, a food safety certificate, the fatty acid source and allergen declaration, and a halal or kosher certificate can be requested.
Which technical properties are important when buying Potassium Stearate?
Purity, K₂O, free fatty acids, free alkali, unsaponifiable matter, moisture, heavy metals, fatty acid composition, form, shelf life and packaging are important.
POTASSIUM STEARATE – TECHNICAL SUMMARY
Chemical name: Potassium stearate; potassium octadecanoate; stearic acid potassium salt
Common name: Potassium Stearate, Potasyum Stearat, E 470a
CAS No: 593-29-3
EC / EINECS No: 209-786-1
Molecular formula: C₁₈H₃₅KO₂
Molecular weight: 322.57 g/mol
Chemical class: Saturated fatty acid salt; anionic surfactant; potassium soap
Physical appearance: White or creamy white powder, flakes or semi-solid substance
Main properties: Slightly soluble in cold water, soluble in hot water and ethanol, density about 1.12 g/cm³, melting point above 200 °C, alkaline aqueous solution
Main functions: Emulsifier, anticaking agent, release agent, lubricant, co-thickener, cleansing agent
Important fields of application: Cake gel and cake, margarine, non-dairy cream, powdered foods, tablet products, cosmetics and soap, plastic and synthetic rubber
Parameters critical for quality control: Purity, K₂O, free fatty acids, free alkali, unsaponifiable matter, moisture, heavy metals, fatty acid composition, food grade documents
Storage: In a cool, dry and ventilated area, in closed packaging; separate from moisture, heat, strong oxidizers and acids
Regulation: Food additive E 470a in the EU, covered by 21 CFR 172.863 in the USA; natural-origin fatty acid salts fall under the REACH Annex V exemption; not covered by dangerous goods transport in most SDSs; conditions and permissions of use should be confirmed with the supplier and the current legislation
