"A practical supplier guide to citric acid anhydrous (CAS 77-92-9): what the water-free grade is, its spec sheet (C6H8O7, MW 192.12, EINECS 201-069-1, white crystalline powder, assay >=99.5%), how it is used across food, pharma, cosmetics, metal cleaning and wastewater treatment, plus buyer specification and storage notes."
-Deshangchemical-chemechemi
Citric Acid Anhydrous (CAS 77-92-9): The Water-Free Workhorse Behind Food, Pharma, and Clean Surfaces
If you have ever checked the ingredient label on a soft drink, a jar of jam, a tube of effervescent tablets, or a bottle of shampoo, you have almost certainly met citric acid. What buyers in the trade usually ask for by name, though, is the anhydrous grade — citric acid anhydrous, CAS 77-92-9. “Anhydrous” simply means the water has been removed during production, leaving a dry, free-flowing crystalline powder that is more concentrated and more stable in storage than the monohydrate form. For formulators who need predictable dosing and a long shelf life, that difference matters more than it sounds.
What the spec sheet says
Before we get into applications, here is the data most procurement teams look at first. The numbers below reflect the typical commercial grade we supply; always confirm the certificate of analysis for the specific lot you receive.
| Property | Typical value |
|---|---|
| CAS number | 77-92-9 |
| EINECS | 201-069-1 |
| Molecular formula | C6H8O7 |
| Molecular weight | 192.12 g/mol |
| Appearance | White crystalline powder or colorless crystals |
| Assay (anhydrous basis) | ≥ 99.5% |
| Solubility | Freely soluble in water and ethanol |
| Storage | Cool, dry, sealed container, away from moisture |
Because the anhydrous form holds no water of crystallization, it is the preferred choice when moisture content would interfere with a downstream reaction or with a finished product’s stability — a common concern in both food tablets and certain pharmaceutical preparations.
In food and beverages: acid, preservative, and texture partner
Citric acid is one of the most widely used acidulants in the world, and the anhydrous grade earns its place on the line for three jobs at once. First, it adjusts pH and delivers the clean sour note that balances sweetness in carbonated drinks, juices, and candies. In beverages the typical addition level sits around 0.1%–0.4%, enough to sharpen flavor without pushing the product into an unstable, over-acidic range.
Second, it acts as a preservative and chelating agent, tying up metal ions that would otherwise accelerate oxidation and spoilage. Third, it controls texture: in candies and jams it inhibits the recrystallization of sucrose, keeping the mouthfeel smooth instead of grainy. That anti-crystallization effect is why you will often see citric acid working alongside gelling and thickening agents such as konjac glucomannan (CAS 37220-17-0), where the two together build a stable, pleasant gel structure.
Flavor houses also lean on citric acid to round out profiles. When a formula calls for a sweet, caramel-like note, pairing it with ethyl maltol (CAS 4940-11-8) gives a warmer, fuller taste than either ingredient alone — a small trick that shows up across confectionery and bakery applications.
In pharma and cosmetics: the quiet pH regulator
Move from the kitchen to the lab and citric acid keeps working, mostly behind the scenes. In pharmaceutical preparations it serves as a buffer and solvent aid, holding pH in a range that keeps an active ingredient stable. In cosmetics it does the same job in skin care and haircare: it fine-tunes the pH of a formula so the skin’s acid mantle is respected and the actives stay effective.
This is where it connects naturally to the rest of a formulator’s toolbox. Citric acid is frequently used in the same products as L-ascorbic acid (CAS 50-81-7) — vitamin C — where careful pH control keeps the vitamin stable and active. It pairs with brightening agents such as kojic acid (CAS 501-30-4) and alpha-arbutin (CAS 84380-01-8), and with emollients like squalane (CAS 111-01-3) that need an acidic environment to stay shelf-stable. In peptide and amino-acid systems — think GHK-Cu copper peptide (CAS 49557-75-7) or sodium lauroylsarcosinate (CAS 137-16-6) — citric acid is the buffer that keeps the chemistry predictable from batch to batch.
In industry and the environment: cleaning and chelation
Citric acid’s ability to grab metal ions is not just a food-safety feature; it is the reason it works as a mild, biodegradable descaler and cleaner. In metal surface treatment it helps remove oxide layers (think rust and tarnish) without the harshness of strong mineral acids, and it leaves a surface that is easier to rinse and passivate. Textile processors use it as a dyeing auxiliary to improve fiber penetration, and formulators of detergents and plasticizers build citrate esters from it as a renewable feedstock.
Environmental applications are growing too. Because citric acid binds tightly to heavy metals such as lead and cadmium, it is used in wastewater treatment to chelate those ions and help pull them out of effluent — a gentler alternative to many legacy treatment chemicals.
How buyers should specify it
If you are placing an order, a few points will save you a rejected lot. Start with grade: food and pharmaceutical uses require the corresponding food- or pharma-grade certification, while industrial cleaning can usually accept technical grade. Confirm the assay on the anhydrous basis and check loss-on-drying, since that is the number that distinguishes anhydrous from monohydrate in practice. Packaging is typically 25 kg woven or kraft bags with an inner PE liner; for humid climates ask about double lining. Store in a cool, dry, well-sealed space — the powder is hygroscopic and will pick up moisture from the air if the container is left open.
MOQ and lead time depend on grade and destination, and we can supply both small lab quantities and full-pallet or container loads. If your formulation also calls for a protected amino acid or a pharma building block, we can combine shipments with items such as creatine monohydrate (CAS 6020-87-7) or Boc anhydride (CAS 24424-99-5) to simplify your sourcing.
Bottom line
Citric acid anhydrous (CAS 77-92-9) is one of those ingredients that looks boring on paper and turns out to be indispensable on the bench. Its acid regulation, chelation, and antioxidant behavior touch food, pharma, cosmetics, cleaning, and environmental treatment — often in the same facility. If you want the full data sheet, packaging options, and current pricing, the product page for citric acid anhydrous (CAS 77-92-9) has the details, and our team can send a COA on request.
