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Abstract The current high consumption of coffee globally has an impact on the abundance of by-products of coffee processing in the form of cherry pulp which are considered waste and cause environmental problems. The waste from arabica coffee is potential economic value products such as fermented vinegar because of its rich nutrients. The aim of this research was to determine the optimal conditions for acetic acid fermentation and the influence of yeast concentration and nitrogen sources fermented for 60 days. The research was carried out in two stages of fermentation using the Orleans method. Anaerobic alcohol fermentation (20 days) followed by aerobic acetic acid fermentation (40 days). A Randomized Block Factorial Design was used with 2 factors, namely yeast concentration (S1 5% and S2 10% ) and NPK (N1 0g , N2 5g , and N3 10g ), repeated 3 times. Observations on alcoholic fermentation were carried out every 5 days for 20 days regarding ethanol levels. Meanwhile, in acetic acid fermentation, 2.5% vinegar starter was added for each treatment and observations were made every 10 days for 40 days regarding the yield, acetic acid content, pH value and total dissolved solids. The results showed that the highest formation of acetic acid was obtained on day 30 of fermentation. The highest acetic acid content was obtained in the treatment S2 10% : N2 5g of 5.27%, pH value of 3.46, TSS value of 0.49 °Bx with a total yield of 42.93%. This is in line with the ethanol content previously formed on day 20 of 11.04% in the same treatment. This value meets the quality standards for fermented vinegar according to SNI 01-4371-1996 by at least 4%.
Martunis et al. (Sat,) studied this question.