Penelitian ini bertujuan untuk mengetahui pengaruh lama fermentasi terhadap total asam, total bakteri asam laktat dan warna L*a*b* dari water kefir buah belimbing manis. Rancangan penelitian yang digunakan adalah rancangan acak lengkap (RAL), dengan 4 perlakuan dan 5 kali ulangan. Perlakuan yang diteliti adalah variasi lama fermentasi yaitu 12 jam (t1), 24 jam (t2), 36 jam (t3), dan 48 jam (t4). Water kefir dibuat dari belimbing manis dengan menggunakan grain water kefir sebanyak 5%, sukrosa sebanyak 8%(b/v). Hasil penelitian menunjukkan bahwa lama fermentasi yang berbeda memberikan pengaruh nyata terhadap total asam, total bakteri asam laktat, nilai L* warna dan nilai a* warna serta tidak berpengaruh secara nyata (p>0,05) pada nilai b* warna. Semakin lama fermentasi dapat meningkatkan total asam, total bakteri asam laktat, nilai L* warna serta menurunkan nilai a* warna.Kata kunci: Bakteri asam laktat; belimbing manis; water kefirFermentation Time Effect on Total Acid, Total Lactic acid Bacteria Color of Star Fruit Water KefirABSTRACTThis study aims to determine the effect of fermentation time on total acid, total lactic acid bacteria and color lab of sweet star fruit water kefir. The research design used was a completely randomized design (CRD), with 4 treatments and 5 replications. The experimental treatments were variation of fermentation time of 12 hours (t1), 24 hours (t2),36 hours (t3), and 48 hours (t4). Water kefir is made from sweet starfruit using 5% water kefir grains and 8% sucrose. The results showed that different fermentation time had a significant effect on total acid, total lactic acid bacteria, color L* value and color a* value and had no significant effect (p.0,05) on color b* values. The longer the fermentation will increase the total acid, the total lactic acid bacteria, the L* color value and decrease the a* color value.Keywords: Lactic acid bacteria; star fruit; water kefir