Citric acid monohydrate is a crystalline form of citric acid that holds one molecule of water inside the crystal for every citric acid molecule. It is one of the most widely used food-grade acids in global manufacturing. It has the same core acidity as anhydrous citric acid once it is dissolved, but the crystal water can change how it handles on the shop floor, including flow, bulk density, and dosing by weight.
If you are comparing forms, remember this simple rule: in solution, both forms behave the same, but in storage and processing, the solid form can behave differently.
What is citric acid monohydrate?
What is citric acid monohydrate?
It is citric acid supplied as the monohydrate crystal, written as C6H8O7·H2O. Industrially, it is usually made by fermenting sugar solutions with microbes such as Aspergillus niger, then purifying the acid and crystallising it as the monohydrate. The term monohydrate means the crystal lattice contains bound water. This slightly increases molecular weight compared with the anhydrous form, so mass-based dosing calculations can shift.
Once dissolved, the water of crystallisation is released, so the acid behaves the same as anhydrous citric acid in terms of pH control and chelation.
Key characteristics of citric acid monohydrate
1) Chemical makeup
Citric acid is a tricarboxylic alpha-hydroxy acid. A simple backbone view is HOOC-CH2-C(OH)(COOH)-CH2-COOH. The monohydrate form is expressed as C6H8O7·H2O.
Because this form contains one extra water molecule in the crystal, its molecular weight is about 210.14 g/mol, compared with about 192.12 g/mol for anhydrous citric acid. This matters when you dose by mass and want an exact acid equivalent.
In the market, it is commonly supplied as food grade , pharmaceutical grade, and industrial or technical grade for non-ingested uses. We at Scimplify supply an IP grade material with assay typically in the 99.5 to 100.5 percent range and controlled heavy metals limits.
2) Appearance
This ingredient typically appears as colourless to white crystals, granules, or crystalline powder. It is odourless, with a clean sour taste.
In many production settings, crystal habit affects dusting and flow. We provide IP-grade as free-flowing crystals that dissolve quickly, suited for syrups, jellies, beverages, and oral pharmaceutical suspensions.
3) Solubility
It is soluble in water, and solubility increases with temperature. This makes it easy to use in beverages, syrups, and cleaning solutions.
It is also compatible with certain polar organic solvents in practical formulation work. In practice, once dissolved, there is no meaningful difference in acid behaviour between monohydrate and anhydrous forms.
4) Stability and storage
This material is stable under normal conditions, but it can pick up moisture from humid air. Over time, high humidity exposure can cause caking or clumping, especially in opened bags or poorly sealed containers.
Good storage basics:
- Keep it cool and dry
- Use tightly sealed inner liners
- Avoid storing near strong bases or oxidising agents
Many suppliers state a shelf life of around 1-2 years for properly stored material.
At high temperatures, citric acid does not boil; it decomposes. So avoid unnecessary heat during drying, blending, or processing steps when you want to preserve quality.
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Common uses by industry
1) Food and beverage
This is one of the most used acidulants worldwide.
Typical roles include:
- Acidulant and flavour balancing, for tartness in soft drinks, juices, energy drinks, candies, jams, and jellies
- pH control that supports preservation, often alongside preservatives such as benzoates or sorbates
- Chelation of trace metals like iron and copper, which can slow oxidation and help colour stability
It highlights this use across beverages, syrups, jellies, and confectionery-style products where quick dissolution and consistent acidity are important.
2) Pharmaceuticals and nutraceuticals
In pharma, this form is widely used as an excipient because it can adjust pH, buffer with citrate salts, and support stability in formulations. Common uses include:
- Oral liquids and suspensions as a pH adjuster
- Effervescent tablets and powders, when paired with carbonates or bicarbonates
- Lozenges and syrups for taste and pH control
It is used in syrups, suspensions, lozenges, and effervescent formulations as a stabiliser and pH buffer.
3) Cosmetics and personal care
In personal care, it is mainly used for pH adjustment and formulation support. It helps bring products into skin-friendly ranges and can improve preservative performance by keeping systems slightly acidic.
pH stabilisation in shampoos, lotions, and skincare products, and metal chelation can support formulation stability.
4) Cleaning and industrial uses
It is a popular choice for eco-oriented cleaning because it offers acidity plus chelation with relatively mild handling compared with strong mineral acids.
Common roles include:
- Descaling, limescale removal, and hard water mineral binding
- Performance support in dishwashing and some laundry systems
- Light rust or oxide film removal on certain surfaces
Used in biodegradable cleaning agents, including scale removal and hard water mineral binding.
5) Other applications
Beyond the big categories, it is used as a lab reagent and in some metal finishing baths, as well as DIY products like bath bombs and home cleaners.
Handling and safety
Citric acid monohydrate has low acute toxicity and is widely used in foods, but safe handling still matters, especially at an industrial scale.
Irritation and exposure
- Dust or concentrated solutions can irritate the eyes
- Prolonged skin contact can cause dryness or irritation
- Fine dust inhalation can irritate the nose and throat
Good handling practices
- Wear safety goggles and gloves during handling
- Use a dust mask or respirator if dust generation is likely during bag dumping
- Provide good ventilation or local exhaust where powders are transferred
- Avoid eating or drinking in handling areas, and wash hands after work
Storage and transport
- Store in sealed, labelled containers with inner liners
- Keep dry and away from strong bases and oxidising agents
- Protect from moisture to reduce caking and maintain flow
Disposal
Small amounts of dilute solutions are often neutralised and disposed of according to local rules. For large-scale or industrial disposal, follow site waste procedures and local environmental regulations, with attention to effluent pH.
Always consult your supplier's SDS for hazard classification, exposure guidance, and emergency measures in your jurisdiction. Scimplify ensures that it provides SDS documentation and technical specifications for regulatory compliance.
Conclusion
Citric acid monohydrate is a versatile, easy-to-use acidulant and chelator across food, pharma, personal care, and cleaning applications. Once dissolved, it behaves like anhydrous citric acid, but in solid form, it can offer practical advantages in handling and quick dissolution.
Confirming the right grade, purity, and particle size for the process, and reviewing the supplier's COA, TDS, and SDS is important for consistent results. Scimplify positions its citric acid monohydrate as an IP grade product supplied as free-flowing crystals, with quick dissolution for syrups, jellies, beverages, and oral suspensions, and with defined assay and heavy metals controls.
With basic PPE, dust control, and dry storage, this ingredient remains one of the most dependable food-grade acids used in modern manufacturing.
