Overview
ISO 5984:2022 - Animal feeding stuffs - Determination of crude ash specifies a standardized laboratory method to determine crude ash content in animal feeds. The method requires carbonization of a representative test portion followed by incineration at (550 ± 25) °C in a muffle furnace and gravimetric determination of the residual ash. Results are reported as a mass fraction (percent) of the sample, typically to the nearest 0.1%. This third edition updates procedure options (including direct cold-furnace programming), instrumentation allowances (thermocouple sensors), and precision limits.
Key topics and technical requirements
- Principle: Carbonize sample, incinerate at 550 ± 25 °C, cool and weigh the ash residue.
- Sample size & prep: Typical test portion ~5 g prepared in accordance with ISO 6498 (sample preparation).
- Apparatus:
- Analytical balance (readability 0.001 g)
- Electrically heated muffle furnace with pyrometer or thermocouple
- Drying oven (103 ± 2 °C), hot-plate or gas burner, desiccator
- Incineration dishes (platinum, porcelain, quartz or other inert materials)
- Procedure options:
- Progressive carbonization on a hotplate then transfer to a preheated furnace
- Alternative: place dishes in a cold furnace and use a gradual heating program to avoid sample projections (recommended programmable controller)
- Result expression: Gravimetric calculation using dish tare, dish + sample, and dish + ash masses; report to 0.1% and average replicates when repeatability criteria are met.
- Precision & performance:
- Interlaboratory data support applicability from 0–1 000 g/kg (tests covered 15–200 g/kg)
- Repeatability (r) and reproducibility (R) limits are provided (examples include r ≈ 2–5 g/kg or 5% relative, R ≈ 3–10 g/kg or 10% relative depending on concentration)
- The standard defines conditions under which results between labs/operators are expected to agree.
Applications and users
ISO 5984:2022 is used to determine ash content - an indicator of total mineral matter - in a wide range of animal feeding stuffs (feeds, meals, molasses, cereals, by-products). Typical users include:
- Feed testing laboratories and quality control analysts
- Feed manufacturers performing raw material and product specification checks
- Regulatory and inspection bodies verifying compliance with labeling or composition limits
- Research institutions studying feed composition and nutrient/contaminant balances
Practical benefits: consistent, reproducible ash results for product specification, formulation, traceability, and regulatory compliance. The crude ash residue can also be used for subsequent tests (e.g., ash insoluble in HCl per ISO 5985).
Related standards
- ISO 6498 - Sample preparation for animal feeding stuffs
- ISO 5985 - Determination of ash insoluble in hydrochloric acid
- ISO 5725-1 / ISO 5725-2 - Accuracy, repeatability and reproducibility of measurement methods
- NF V18-101 - National reference for crude ash repeatability guidance
Keywords: ISO 5984:2022, crude ash, animal feeding stuffs, determination of crude ash, muffle furnace, incineration, ash content, repeatability, reproducibility.