It is known that defective coffee grains drastically affect the quality of the final drink; however, it is not yet known at which concentration it starts to happen. The goal of this work was to define descriptive terms that may characterize drinks prepared with arabic coffee containing different concentrations of defective grains (Black, immature and sour grains – BIS), using the focus group methodology. Six coffee drinks were evaluated, with concentrations of 0%, 2%, 26.5%, 51%, 75.5% and 100% of defective grains. Coffee drinks’ consumers were selected and answered questions related to their consumption frequency and worries about the quality of coffee. Three sessions of focus group were performed composed by a total of 20 participants. Results of the socio-demographic survey showed that most participants were women (65%), with incomplete post-graduation degree (65%), are daily coffee consumers (80%), and are worried about the quality of the coffee (80%). The samples were described by characteristics of appearance, flavor, taste, emotional terms and affective terms. There was no pattern amongst the consumers when it came to descriptive terms about the samples. It was not possible to describe each one of the samples separately, because there was a great diversity of opinions and consequently many descriptions. Many of the participants described the sample with 100% defect as the best: “Perfect bitterness”,” Brazilian Coffee”, “Delicious”. The sample with 0% defect wasn’t so well described as expected: “Deception”, “More water than coffee powder”, “Old Coffee”. Drinks prepared with intermediate defective grains concentrations (51 and 75.5%) were described as: “Coffee from the Market”, “Coffee that I’m used to drink”, “Certainly would buy”. In conclusion, defective grains do not seem to have a negative influence on the participants’ drink acceptance, since the samples with highest levels of defective grains were the ones with better descriptions.