Background. In the article, changes in the chemical properties (pH, sugar content) of a fermented tea beverage during a fermentation process and the influence of the above properties on the sensory characteristics of the final product were analyzed.
Results and conclusions. On average, the sugar content decreased by 10.6 % on the sixth fermentation day, the decrease in sugar content at its highest on the sixth fermentation day was observed in the peppermint tea sample (18.7 %), while the reduction at its lowest was observed in green tea with additives (ginger and lemon – 8.0 %; ginseng and lemon – 6.5 %) and black tea (8.1 %). The average pH value was 3.13 ± 0.15 – i.e., lower than 4.2, and if that level is achieved, scientific literature recommends stopping the fermentation process due to the possible negative impact of the beverage on health; the pH of green tea samples without additives was higher than the average (3.13 ± 0.15) – 3.20 ± 0.12 (peppermint), 3.23 ± 0.15 – green tea, while the pH of the black tea sample was 3.0 ± 0.20 – lower than all the samples tested. A positive correlation was specified between the sugar content, the pH change and temperature, however, it is of different strength: the relationship between the pH and temperature was medium (r = 0.682); while the relationship between the sugar content and temperature was low (r = 0.305).