Geurtests

Geurtests are sensory evaluations that focus on odors. They rely on trained human assessors to measure odor strength, quality and hedonic value, and may be complemented by instrumental methods such as electronic noses or GC-olfactometry. The main purpose is to quantify and describe odors for regulatory compliance, environmental monitoring, product development, or quality control.

The core method in geurtests is dynamic olfactometry, where a panel is exposed to controlled dilutions of a sample in clean air and asked to indicate when an odor is detectable. Results are typically reported as odor concentration in odor units per cubic metre (ou_E/m3). Other approaches include descriptive analysis to characterize odor notes (for example fruity, sulfurous, floral), threshold testing to determine minimum detectable concentrations, and hedonic testing to assess pleasantness. Instrumental approaches can provide objective patterns but generally do not replace human perception in odor evaluation.

Standards and guidelines support geurtests, with EN 13725 being a prominent reference for dynamic olfactometry. Additional standards cover sensory analysis of aroma and intensity, and laboratories often use trained panels, calibration exercises, and inter-laboratory comparisons to ensure consistency and reliability.

Applications of geurtests are wide, including assessment of odor impact from wastewater treatment plants, landfills, and other industrial facilities; aid to product development in food, beverages, cosmetics, and fragrances; quality control; and regulatory reporting to authorities concerned with odor nuisance or air quality.

Limitations include subjectivity and inter-individual variability among panelists, adaptation effects, and the need for rigorous training, scripting, and quality assurance to maintain reproducibility across measurements.