Validating the Sensitivity of the Beer Tetrad Test as Compared with the Beer Triangle Test: An American Society of Brewing Chemists Technical Committee Report

Abstract

This subcommittee was formed based on the recommendation of the American Society of Brewing Chemists (ASBC) sensory subcommittee. Its purpose was to determine if the Tetrad Test is as sensitive as the Triangle Test for beer sensory testing. To accomplish this task, 11 sensory panels participated in Tetrad and Triangle testing of two commercially available beers. Half of the samples were stored at 4 °C and the other half were stored at 24 °C. Samples, detailed instructions, and ballots were shipped to each of the participating panels. Each panel returned their results to the Wolf Group for data analysis. The Tetrad Test was found to be a suitable replacement for the Triangle Test. The Tetrad Test had a higher percentage of correct responses at more panel sites than did the Triangle Test. At a confidence level of 95%, no significant differences were observed in the aggregate proportion of correct answers for the Triangle Test versus the Tetrad Test. The reduction of Effect Size (d′) for the Tetrad was less than the theoretical reduction of 1/3, indicating that the Tetrad Test is slightly more powerful than the Triangle Test. The lower standard deviation of the Tetrad Effect Size indicates that it is more precise than that of the Triangle Test. The subcommittee recommended that the Tetrad Test Method be published in the ASBC Methods of Analysis as a suitable alternative to the Triangle Test. The subcommittee also recommended that further testing be conducted to test the tolerances of the Effect Size (d′).