Discrimination sensory tests aim to identify if the difference between two similar stimuli is detectable, having great application in quality control, ensuring that products have the same quality standard. In this study we compared the efficacy of Tetrad and Triangular tests in detecting differences between two guarana soft drinks, by means of the calculation of proportion of discriminators and the thurstonian distance. Samples were produced by different syrup clarification methods (activated carbon and ionic exchange column). For each test 99 tasters were used and samples were presented following a randomized complete blocks design. Only Tetrads test was able to detect significant difference between the samples (p<0.05), proving a better power and sensibility against Triangle test. However, the low proportion of discriminators and thurstonian distance inferior to the perception limit suggest that a small amount of consumers would be able to detect differences between the two samples of guarana soft drink produced by different simple syrup clarification methods.