hi;
I used Fresh white grape juice ( made through crushing and pressing), no sugar added. I just added bisulphite (1.8 Gr/15 Liter total) in a plastic barrel. The sugar level was 23 Bx. After 48 hrs, I racked it to a glass carboy and added Yeast(dosage regulated according to instruction), and sealed the carboy with a stopcock I stirred it everyday during frist 2 weeks which accompanied with PH of 3.4 and sugar level drop to 12 Bx. during 3rd-5th week i stirred it twice weekly but i noted no change in sugar level but a decreasy in acidity up to 3.9. On advice of a friend, i stopped stirring and just tested it for PH and sugar every other day. when after month 2, i recorded a PH of 3.6 and sugar level of 8. I got happy asif everything was working well, the taste was fruity and sweet ofcourse. 2-3 days after this record, despite everything was unchanged(Ph and sugar), I tasted vague bitterness in it. The ambient temp. during whole procedure has been within 15-20 degrees of centigrade.
Thanks for help and waiting for your soonest advice.
Mehrdad