Overview
EN ISO 11136:2017/A1:2020 is Amendment 1 to ISO 11136 (Sensory analysis - Methodology). It provides updated, normative guidance for conducting hedonic tests with consumers in a controlled area (consumer acceptability and preference testing). This European adoption (CEN) of ISO 11136:2014/Amd 1:2020 clarifies statistical procedures, sample‑size calculations and example workflows for preference, difference and non‑inferiority hedonic tests.
Key topics and technical requirements
- Test context: Hedonic (liking) and preference tests conducted in a controlled test area (laboratory or test booth setting).
- Hypothesis types: Guidance for bilateral (two‑sided) and unilateral (one‑sided) hypotheses, including difference and non‑inferiority formulations.
- Statistical procedures: Updated formulas and worked examples in Annexes F, G and H for:
- Preference proportions (p), difference δ definitions and caution about alternate definitions of δ.
- Sample‑size and power calculations (examples: n = 259 for p difference 0.20; unilateral case n = 211; larger examples up to n = 853).
- Use of t‑statistics, pooled within‑product variance, and degrees of freedom for t‑tests.
- Practical calculation notes showing Excel functions (T.INV.2T, T.INV, T.DIST) for critical t and cumulative probabilities.
- Worked examples: Step‑by‑step numerical examples for calculating t, β (type II error), and power - useful for planning and reporting.
- Reporting and interpretation: How to conclude on significant preference or non‑inferiority based on t vs. critical values and power considerations.
Practical applications
- Design and execution of consumer acceptability studies for food, beverage, personal care and other sensory products.
- Determining sample sizes and statistical power when comparing two products for preference or equivalence.
- Supporting product development decisions (reformulation, optimization) and substantiating marketing claims about consumer preference.
- Standardizing test procedures in sensory labs to produce reproducible, defensible results.
Who should use this standard
- Sensory scientists and sensory laboratories
- Product developers and R&D teams in food, beverage, cosmetics, household products
- Quality assurance specialists and statisticians supporting consumer testing
- Consultants and contract research organizations offering consumer hedonic tests
Related standards
- ISO 5495 (mentioned in the amendment) - preference test terminology and methods referenced for two‑product ranking/preference procedures.
EN ISO 11136:2017/A1:2020 is essential for practitioners who need robust, standardized methods for consumer hedonic testing with clear statistical guidance for planning, analysis and interpretation. Keywords: EN ISO 11136:2017/A1:2020, sensory analysis, hedonic tests, consumer testing, controlled area, sample size, statistical power, preference test.