ISO 6673:2003

Overview

ISO 6673:2003 is an international standard established by the International Organization for Standardization (ISO) that specifies a precise method for determining the loss in mass of green coffee at 105 °C. This method is applicable to both decaffeinated and non-decaffeinated green coffee, as defined in ISO 3509. The primary focus of this procedure is to quantify moisture and volatile content through heating, which equates, by convention, to the water content of the green coffee. However, it should be noted that the moisture results from ISO 6673:2003 are approximately 1.0% lower than those from the reference method detailed in ISO 1446.

Key Topics

• Scope and Application This method targets the measurement of mass loss at 105 °C, primarily reflecting water and minor volatile losses in green coffee samples. It is intended for use by laboratories analyzing incoming raw coffee beans or quality control processes.

• Principle of the Method The technique involves heating a representative coffee sample at a controlled temperature of 105 °C for 16 hours at atmospheric pressure, allowing water and volatiles to evaporate, thereby reducing the sample's mass.

• Apparatus Requirements

  • Electrically heated oven with ventilated temperature control at 105 °C ± 1 °C
  • Hermetically sealable capsules (aluminum, stainless steel, or glass) approximately 90 mm in diameter and 20-30 mm in height
  • Analytical balance with precision to 0.1 mg
  • Desiccator with effective drying agent (e.g., anhydrous calcium sulfate or silica gel)

• Sample Preparation and Testing Procedure

  • Capsules are pre-dried, cooled, and weighed.
  • Around 10 grams of green coffee grains are evenly placed into each capsule.
  • Capsules are covered, weighed, and subjected to drying at 105 °C for about 16 hours.
  • After drying, capsules are cooled in a desiccator and reweighed to measure mass loss.
  • Duplicate determinations are recommended to ensure accuracy.

• Result Calculation Mass loss percentage is calculated by comparing the initial and final masses of the coffee sample in the capsule, excluding the capsule's own mass, and expressed as a percentage.

• Precision and Reproducibility The standard includes statistical evaluation from interlaboratory trials involving 14 laboratories to establish repeatability and reproducibility limits, ensuring reliable and consistent results across facilities.

Applications

ISO 6673:2003 is essential for various stakeholders involved in the coffee industry, including:

• Quality Control in Coffee Production Allows producers to measure moisture content reliably, ensuring green coffee meets storage and processing requirements.

• Import and Export Compliance Provides a standardized testing method to verify moisture levels during trading, vital for avoiding spoilage and complying with contractual agreements.

• Research and Development Supports coffee researchers studying the effects of moisture on bean quality, storage life, and roasting characteristics.

• Calibration and Reference Use Laboratories may use this method as a routine moisture assessment tool and calibrate other moisture determination methods against the ISO 1446 reference method.

Related Standards

• ISO 3509 - Vocabulary for coffee and its derivatives, providing standardized definitions critical to ISO 6673:2003.
• ISO 1446 - Fundamental reference method for determining water content in green coffee, essential for calibrating alternative moisture methods including ISO 6673.
• ISO 4072 - Sampling method standard for green coffee in bags, which aids in preparing representative samples for testing by ISO 6673.
• ISO 5725 series - Guides on accuracy, repeatability, and reproducibility of test methods, underpinning the reliability requirements detailed in ISO 6673.

Keywords: ISO 6673:2003, green coffee, loss in mass determination, moisture content, coffee testing standard, coffee quality control, coffee moisture analysis, decaffeinated green coffee, coffee drying method, ISO coffee standards.