ISO 3432:2008

Overview

ISO 3432:2008 (IDF 221:2008) defines the design and marking requirements for the butyrometer used in the Van Gulik method for determining cheese fat content. This standard does not prescribe the analytical procedure itself (see ISO 3433/IDF 222 for the method); rather it specifies the physical characteristics, graduations, stoppers and optional weighing devices so that results from cheese fat determinations (0–40 % mass fraction) are reproducible and comparable across laboratories and suppliers.

Key topics and technical requirements

• Scope: Butyrometer characteristics for the Van Gulik fat determination in cheese covering 0 % to 40 % fat mass fraction.
• Material: Clear glass, resistant to thermal shock and reagents used in the Van Gulik method.
• Construction & shape: Symmetrical outer surface, smooth internal surface, flat-bore graduated tube (back surface not frosted).
• Capacity & dimensions: Body volume between levels Y and Z = 21.0 ± 0.5 ml (without weighing device). Wall thickness ≥ 0.9 mm; external neck diameter ≤ 25 mm. Scale length 71 ± 7 mm.
• Graduation & scale: Range 0 to 40 % fat, 80 graduations at 0.5 % intervals; intermediate 1 % and full-length/numbered lines at each 5 %; maximum permissible volume deviation 0.25 % (half a division). Basis of graduation: 1.354 ml at 20 °C = 40 % mass fraction.
• Graduation line quality: Etched, uniform thickness 0.1–0.2 mm, short lines 3–4 mm, intermediate lines project ≥1 mm beyond short lines, numbered at every 5 %.
• Inscriptions: Permanent marking required - “CHEESE Van Gulik 65 °C”, “ISO 3432│IDF 221” (or national equivalent), and maker’s name/mark.
• Stoppers: Material hardness (38 ± 5) IRHD; shape/dimensions specified; optional central hole if using certain weighing devices.
• Weighing devices: Illustrative suitable devices shown; alternative non-reactive devices permitted if they do not affect results.

Applications and users

ISO 3432:2008 is essential for:

• Dairy laboratories performing cheese fat content analysis by the Van Gulik method.
• Quality control and compliance testing in cheese production and processing.
• Manufacturers and suppliers of laboratory glassware and butyrometers.
• Accreditation bodies and test method developers ensuring equipment conformity. Using butyrometers built to ISO 3432 enhances comparability of fat determinations across labs and suppliers, supporting regulatory compliance and product labeling.

Related standards

• ISO 3433│IDF 222 - Cheese - Determination of fat content - Van Gulik method (specifies the analytical procedure referenced by ISO 3432).

Keywords: ISO 3432:2008, butyrometer, Van Gulik method, cheese fat content, fat determination, ISO/IDF standard, dairy laboratory equipment.