Phosphoric acid (H₃PO₄) is a versatile mineral acid used across food and beverage, metal treatment, fertilisers, detergents and water treatment. Most commercial supply is the familiar 85% concentration — but the grade you choose matters as much as the strength.
Grade is about purity and intended use
The headline number, 85%, refers to concentration and is common to both grades. The difference is purity and the controls behind it:
- Food grade phosphoric acid meets the purity and contaminant limits required for use in food and beverage processing — for example as an acidulant. It’s produced and handled to food-safety expectations and typically comes with appropriate documentation.
- Technical / industrial grade is intended for non-food applications such as metal surface treatment (phosphating), chemical processing, fertilisers and cleaning formulations. It’s perfectly suited to those uses but is not appropriate where food contact is involved.
The practical rule: if the acid touches food or beverage, specify food grade. For everything else, technical grade is usually the cost-effective choice.
Where each grade is used
| Application | Typical grade |
|---|---|
| Food & beverage acidulant | Food grade |
| Metal phosphating & surface prep | Technical grade |
| Fertilisers & agrochemicals | Technical grade |
| Detergents & cleaning | Technical grade |
| Water treatment | Technical grade |
What to specify when you enquire
- Grade (food vs technical/industrial)
- Concentration (commonly 85%)
- Packaging (e.g. 35 kg cans, carboys, or bulk)
- Documentation needed (COA, SDS, and for food grade, the relevant compliance documents)
- Quantity and delivery city
Handling and storage
Phosphoric acid is corrosive. Store in compatible containers in a cool, dry, ventilated area away from alkalis and reactive metals, and handle with acid-resistant PPE. When diluting, add acid to water — never the reverse. Review the SDS before handling and request a COA for batch-specific assay.
The bottom line
Concentration tells you the strength; grade tells you whether it’s fit for your application. Tell us your use case and whether food contact is involved, and we’ll confirm the right grade, packaging and documentation — and quote it within 24 hours.
