Widely consumed by Amazonian communities, fermented açai offers new flavors while maintaining the fruit's nutritional properties. This study aimed to compare fermented açai from fresh açai pulp. Total aerobic mesophilic plate count (TAMPC), Lactic Acid Bacteria (LAB), and total polyphenols (TP) and anthocyanins were monitored at the beginning and after 24 hours of spontaneous fermentation. The fruits were collected from Abaetetuba/PA (ABAET) and São Sebastião da Boa Vista/PA (SSBV). Açai pulp was prepared using a vertical pulper with water at 1Kg of fruits: 0.7L ratio, and packaged in 500 mL bottles covered with cloth. After 24h  at 28 ± 2.0 ºC, the TAMPC increased from 6.56 ± 0.24 to 10.02 ± 0.40 log CFU/mL (24h) in ABAET, and from 5.80 ± 0.77 to 9.45 ± 0.61 log CFU/mL (24h) in SSBV. LAB represented 5.37 ± 0.48 log CFU/mL (initial) to 9.10 ± 0.29 log CFU/mL (24h) in ABAET and 4.99 ± 0.52 log CFU/mL (initial) to 8.83 ± 0.31 log CFU/mL (24h) in SSBV. Thus, the initial pH of the samples was 4.88 in ABAET and 4.99 in SSBV, which decreased to 4.13 in ABAET (24h) and 4.06 in SSBV (24h) with fermentation progress. The TP content varied from 6.19 ± 0.44 (initial) to 8.62 ± 0.97 gGAE/100g DM (24h) in ABAET, and from 5.56 ± 0.03 (initial) to 14.54 ± 0.15 gGAE/100g DM (24h) in SSBV. Anthocyanins content varied from 1.13 ± 0.27 (initial) to 0.79 ± 0.45 g of anthocyanins/100g DM (24h) in ABAET, and from 1.04 ± 0.29 (initial) to 0.65 ± 0.38 g of anthocyanins/100g DM (24h) in SSBV. Therefore, TP were well-preserved during fermentation, maintaining levels comparable to the fresh beverage. Thus, this justifies the industrial application of the fermented beverage as an alternative to the short shelf life of fresh açai.